The scroll wheel does not work well
597164
The scroll wheel does not work very smoothly. After two months usage, the scrolling produces unpredictable distance and directions and the web page contents are jumping all around. Not sure how to contact the sellers. I hope the seller could contact me about this issue...
2477128
Works fine, but the scroll wheel kind of stuck when I bought it.  Should have returned it, now the sticking is much worse and after taking it apart to clean and examine I can't find any way to fix the problem.
3330857
It's a nice mouse, I use it at work. The scroll wheel doesn't click though, so it is easily brushed and in many cases that can cause stuff to zoom in and out erratically.
73093
overall a poor quality device.  Most clicks fail to register.  The wheel has an inconsistent scroll behaviour.  I have tried to use this on two different machines and modified the device settings.

Support?  non-existent.
3250905
The mouse is good - I really like the thumb button and horizontal scroll wheel.  There is a problem with the software, though - the thumb wheel and forward/back buttons only work intermittently.  I will be working on a large spreadsheet, happily scrolling sideways, and it will just stop, and not work for several minutes, then it will start working again with no indication of why.  It is only the "extra" functions that have this problem, though - "regular buttons and scroll wheel always work.  I like the smart scroll function, too - took some getting used to, but now that i get it, it works well.
365367
The mouse is not working well after a few months. The page scroll wheel is loose and automatically scrolls up & down unwantedly! Also, the left click button doesn't work every time.
158116
The scrollbar got messed up out of nowhere. Scrolling down takes me up- but the guidance of the mouse itself is nice.
1247929
Very good mouse, aside from the scroll wheel.
The scroll wheel is very shoddy, after having it for nearly a month, the scroll wheel is randomly going up when I scroll down. I have no idea if this is a problem with the wheel itself or my computer, but it seems to be an issue with the mouse.
528191
Scrollwheel was almost nonfunctional and mouse didn't track well. Hurt my wrist too, but I'm used to smaller mice so your mileage may vary.
4671662
The mouse shapes nicely in my hands but the scroll is terrible. Not sure if it is broken or if it just terrible. Other than the scroll problem, everything else is pretty good. But since a mouse is no good without scroll, I wouldn't recommend this item.
4075318
I've only had this keyboard and mouse for 3 mouths and the scroll wheel barely even works any more even thow i rarely use. The keyboard works just fine, well even better than i thought it would.
618375
I have been using the mouse for 6 months (a balance of regular use and playing Fallout 4). For the last month or so, the scroll wheel has been acting erratically. Scrolling up would randomly result in a scroll-down, while scrolling down randomly result in a scroll-up. Sure, this is a very affordable gaming mouse. Unfortunately, however, that also seems to reflect its build quality and endurance.
264987
Good mouse, but poor design. For some reason, they made it so you can see red light coming out from where the scroll wheel is. This ends up reflecting red light on the screen, which is distracting.
489999
I just bought one of these from "Office Despot", being
desperate after my old mouse failed.  After 15 minutes
use I'm returning it.  The scroll wheel on the one I
bought is uncomfortable, but worse, when I try to
scroll I often get a "scroll wheel button push"
instead.  This happens maybe about half the time, and
I couldn't solve the problem by using a lighter touch
on the scroll wheel.

I use a scroll wheel all the time so this mouse is just
unacceptable for me.
1810872
Scroll wheel stopped working properly after maybe 3 months.  It also wasn't very comfortable to use so I bought an Anker Ergonomic mouse instead and only switch to the CM Storm Xornet when I play games.  I finally decided to reach out to Cooler Master support to see if there is a way to fix the scroll wheel and they told me I need to send it back for a replacement.  The problem is that they want me to pay for shipping and send it back before I can get a new one.  For the amount of $ I spent on this mouse, it was easier to throw it in the trash and just buy something new.  I ran into a similar issue with Anker before and they took care of me so I went ahead and bought an Anker gaming mouse instead.  I also own the CM Storm mechanical keyboard.  I've had that for over a year and it's been working great. The reps @ Cooler Master returned my email promptly and provided the RMA information so I have no issues with those guys.  However, based on this experience, I will not buy another Cooler Master product in the future.
1769738
it feels nice and looks rad, but kinda faulty for example my scroll wheel doesnt work at all after about a month, upsetting, wouldn't recomend. The single click double clicks more than half the time too now.
216567
I like the shape and color of course unfortunately the scroll wheel does not work.  It's really worth $7 not 15