First things first. I needed a large mouse for large hands and I finally stumbled upon this gem of a mouse that feels like it was made for me. (I was using a G502 previously and found it to be to small). So I decided to buy it and found out that it sold out literally everywhere at my place. So I had it shipped to my country through Amazon Global standard shipping(through Aramex) . Arrived a week early and was well packaged but the box had to opened for a customs check. No items were missing , so good.The mouse is really well built and is a bit on the heavier side but I like my mice heavy. The ergonomics are really perfect for large hands (hand size: 19.5x10cm) and the included pinky rest is a lifesaver for both gaming and work. The mouse feet are really smooth, in fact too smooth that I had to lower my sensitivity lol. All buttons can be customized with Corsair iCUE quick and easy and if you need macros that can be done within the software as well. Some features can be saved to the mouse on-board memory profiles (up to 3) so you do not need the software all the time. RGB is bright and beautiful. The outer body has a textured plastic that is miles better than rubber.Wireless : Corsair slipstream is truly an achievement and I found no difference in performance when using the mouse in both wired and wireless mode. iCUE is only required for the pairing the mouse and the dongle. After that you can turn the software off if needed. I've had some lag (that goes away after 5-10 secs) when trying to use the mouse after the computer starts up or awakens from sleep mode however this is a standard phenomena that occurs with all wireless mice. The mouse is a breeze to use without wires. (the included wire is too stiff and can push the mouse on a flat surface if it gets coiled)Battery and charging: Battery life is average. Mouse lasts for about 9-10hrs with all lights turned on and takes about 2-3 hrs to fully charge. Wireless charging is OK , it takes a bit of time but its really well implemented and mouse lights up white to let you know it it is charging wirelessly with any Qi certified charger. Note: There is no percentage indicator letting you know how much battery is left even in software unfortunately.Miscellaneous issues : I have heard of issues of accidental right click and mushy switches in some reviews. At least in my unit , I haven't had such experiences....yet. (will update if any occurs).Cons: The Corsair iCUE software is a pain to use and it literally crashes my PC when trying to game. Button mapping although easy to do gets ages to save in the software and I finally decided just to save it to the onboard profile instead. Also one major problem I found - If you have a low end PC and you also have other corsair peripherals such a s a Corsair keyboard , the software forces you to save multiple (unnecessary) profiles to both software and onboard memory of BOTH keyboard and mouse to function properly. If it is not done it causes a lot of software glitches and unresponsiveness of keys on the keyboard and DPI buttons on the mouse. Also if you uninstall iCUE with keyboard and mouse connected , It will take away the RGB of both devices for some reason. There is also a bug that says 'your profiles are not saved , go to device settings to save' even if I saved the profile to mouse multiple times. The profiles will work but it is an annoyance to see that pop up again. I strongly recommend you disable the software after you have done all your mapping, wireless and macros if you are on a low end device.Verdict: Overall the best ergonomic mouse that I have laid my hands on. They don't make mice like these anymore after most "pro's" switched to ultralightweight mice. Good modular support and ease of use. Only held back by the horrible iCUE software. (P.S -pretty much all mouse software have some issues...although my review thrashes iCUE , I just want you to know that no software is perfect even if it is from Logitech or Razer , it is just a matter of getting used to it until they fix it ).I recommend this mouse.this mouse is pretty good some times on wake it takes a second to sync correctly but only like 1 second i have seen it choke here and there but only when i pair it with a wireless keyboard (might be because adapters are pluged in right next to each other) when paired with my wired keyboard it stays fine i am over all happy with it the icue works great with my icue fans. i use this to replace my death adder razor mouse. now i am looking at replacing my razor keyboard with a k100 but have not pulled that trigger yet it feels heavy and i love that. the pinky rest.... oh my the pinky rest how have we lived this long without them. dpi is fine i can spoon it with big hands ... well if you are on the fence i would say get it if you want a light mouse this is not for you.This mouse is everything I ever wanted in a wireless mouse! Very comfortable, great to look at... The RGB lighting is very stylish. While gaming, the mouse is very responsive and I have had no latency issues with it. The only draw back with this mouse is Rechargeable Battery Life. However, I dropped a USB-C cable down by my monitor, and I throw it on the charger every 3rd night, and I have a full charge ready to go when I come back to the office. I would prefer a longer battery life, but its fair trade off for what you get otherwise. I am still using it and will continue !The first thing I did was get the mouse connected to my PC over bluetoooth, no problem. I installed iCUE and when I opened it, it did not show the mouse. The mouse was working fine! I watched a youtube video and discovered it had to be plugged in via USB before iCUE would see it. What? I plugged it in and then iCUE could see it. Not kidding.It gets worse. I am familiar with how to configure the mouse buttons using Logitech's software and figured iCUE would be similar. Wrong. They took the Microsoft approach and made it as cumbersome as possible. Not only do you have to create a profile for the setup, that is for a game or such, you also have to create profiles for each button within that profile that you wish to change. And changing a button's function is not intuitive, and takes some clicking around to figure it out.Here's the icing on the cake. I could see that the mouse had old firmware and decided to load the newest one via iCUE. It's still connected via USB so all should have to do is click the update button and wait for it to happen. Wrong again! It has to be connected via the WiFi adapter to perform a firmware update! Not kidding!!!The iCUE software is VERY slow. Perhaps it's written in something lame like LabView. I'm a software engineer and very critical of stuff like this. If the app is this bad, I suspect the firmware in the mouse is just as bad, possibly worse.The mouse itself seems fine, feels good, and connects quickly over bluetooth. It was half the price of a Logitech mouse I had my eye on, so I'm going to keep it for a little while and then decide if I will keep it or send it back.--- Edit ---I thought I'd give it another try and decided to edit the button definitions for playing Space Engineers. When I connected the mouse via USB cable and opened the iClueless software, it showed up as blank. There are supposed to be three profiles, and instead I saw none. All of my previous button definitions were gone. So I reprogrammed them, and set DPI up as "f" and DPI down as "g". I opened Notepad and hit DPI up and got an "f" - yea! I clicked DPI down and got an endless repeating string of "g"s that wouldn't stop until I clicked another button. Maybe it was a quirk. I tried it again and got one "f" and "ggggggggggggggggggggggggggggggggggggggggggggggggggggg".What a piece of crap. I'm returning it.At twice the price a Logitech mouse is a far better deal. If all you care about are pretty lights, then this mouse might just work for you.Good- Feels great in the hand, performs well, really does have pretty low latency, iCUE software makes updating and customizing lighting a breeze.Okay- The wireless charging feature does work, but does require a QI wireless charger, and getting the two to pair and start charging is finnicky. Mouse has to be in exactly the right spot.Annoying - The scroll wheel softly squeaks.Overall, I'm happy. But the squeaky wheel in particular feels like something that could have been prevented.This mouse looks beautiful. It's incredible to look at. It works great and with the ICUE software, it doesn't leave much to be desired. With that said, it does leave something and it's not something small. The build quality is awful. It's heavier than almost any other mouse I've had (Not a problem for me, but worth noting) and the right mouse button squeaks almost out of the box. It's not minor, it's a huge issue. I cannot recommend this mouse at all. It squeaks so loudly and constantly. I have so many corsair products, and I swear by them. Their mice just don't hold up. Keyboards, Ram, Fans, Coolers, they're all great. But I've had about 7 different Corsair mice and they've all had some issue. I can recommend Logitech above all for mice. They don't look quite as nice, but they're quality is incredible. I have the G604 now and it's working great. Don't get this mouse if you need to right click anything.It is a comfortable mouse to hold, not too heavy for a wireless mouse either but it's full of issues.The USB receiver gets laggy and causes the cursor to stutter. I did read a bunch of reviews before buying so I was aware of that issue, I didnt really care as my computer sits litteraly next to my mouse (1 feet separates the mouse from the USB receiver and no other wires or anything blocks the signal).Corsair iCue is great, nothing to complain about there. RGB lighting works like a charm and looks phenomenalThe battery life is definetly not what they claim it is, I never even got close to the 50h they claim it lasts. Around 20h is the best I got out of it.The DPI Buttons are really easy to misclick if you have large sized fingers and it gets really annoying when you're playing in game. Not to mention the mouse randomly died after a charge cycle, I opened an RMA with corsair and it decided to come back to life so I cancelled the RMA Ticket.... only to realize it had died once again after 2 other weeks.I am not the only person I know who has/had a Corsair gaming mouse and the same complaints would come over and over again.... Corsair has not figured out yet how to make a good mouse. Don't get me wrong I love corsair, I have a K95 keyboard and Dominator RAM in my computer but man stay away from their mouses. This is coming from a long time PC gamer who loves to try different products. I then sold this mouse and got back to my old loves.. Got a Steelseries Mouse.I bought this to replace another Corsair mouse which, after many years, started having the double-click issue. Given the longevity and feel of that mouse, I decided to upgrade and go for this model as a replacement.The wireless connectivity is great, and is absolutely lag-free which is essential for gaming. Additionally, it is very comfortable to use for long periods of time, such as for work. The side buttons are great are essential for me on any mouse. Qi charging makes it super convenient to keep the mouse charged; just drop it on the charging pad and grab it off next time you want to use it! Dual wireless options (Bluetooth and proprietary dongle) are nice for switching between different devices, such as a desktop and laptop.The biggest problem with the mouse is the scroll wheel. Unlike the last mouse I had, this one only works at slower scrolling speeds. If you try to scroll quickly, it either scrolls extremely slowly, not at all, or jumps around within a few "clicks" of the original position. This does make it a bit annoying to use when working with large files or webpages. At this point, I have gotten used to it, but it is something I do miss from my old mouse.Hopefully by the time I need to replace this mouse there will be a new or similar model which fixes the scrolling issue, because I would absolutely consider getting the improved model of this mouse at that point.Pros:SizeBattery Life (for me personally)The feel of the mouseScroll button feels solid (not weird and loose like Logitech)Pinky attachment or regular side piece for smaller handsDUAL PURPOSE - main feature for me. I use it for my personal PC through USB receiver (gaming Battlefield mostly) as well as Bluetooth connection to my work laptop. It transitions so smoothly when switching using the feature under the mouse.For gaming it is fantastic I notice zero lag/latency.BATTERY LIFE: I use it for work/personal throughout the day. BT is usually used for about 7 hours and USB receiver for about 3-4 hours for a total of roughly 10ish hours per day. One full charge lasts me a solid 4 days with the battery requiring charge at the end of the 4th day.I usually charge it overnight so not a problem for me!Cons:Only one so far is getting use to iCUE software but honestly spend some time learning about it and it’s fine. For the most part I’m not really using iCUE to customize too much so I’m good with it.Overall it’s an amazing mouse I love the feel of it and dual purpose it provides me. Will update in the future if something goes wrong!