While purchasing this mouse I read a lot of mixed reviews (the negative ones mainly being that it dies after a few months) so, I think I can properly describe my experience after a year of heavy usage and try to break it into pros and cons.
Beginning with pros:
1) Wireless (duh)
2) Really silent clicks. So you are free to work/play even if someone's sleeping right next to you (tried it myself :p)
3) In-built battery let's you be free of worry to get new cells. And the charge lasts really long. In my case the battery lasted for like 2-2.5 weeks in a single charge easily (although this might vary if you use with rgb) (i didn't use rgb mode, reason in cons)

That's pretty much all for a the pros part

Cons:
1) It doesn't work in wired mode as mentioned in the description. The way it works being wired is if you keep the wireless dongle plugged in (and basically use 2 ports to run the mouse). Which kind of defeats the purpose of running it in wired mode in my opinion
2) There's no support software that could be found. I tried. I couldn't find it. Hence, you can't program the 2 additional buttons as you want, and neither can you set the rgb light to suit your preference (the rgb just goes though the color cycle, so it ends up being a personal preference to use the rgb mode or not)

That's all I can think of right now.
Conclusion: My overall review stays positive because the cons that I came across doesn't bother much after the initial days, you get used to it. There's very minimal connectivity issues which gets resolved if your just re-plug the device. Otherwise it works fine.
Again, I'm not sure if it's just the piece other users got that ended up dying early or usage patterns. Mine is still working fine after using it for a whole year.
Rating: 4.0
Topics: Battery life