Pros: Construction quality, customizability
Cons: Ergonomics, PTE sensor, 1 side button
From day 1 the mouse never felt quite right and it's really hard to put my finger on it. One is the tracking and two is the ergonomics.
As far as I'm concerned the body of the mouse is too fat, I can't figure out how they intended you to grip it, but everything I tried felt wrong. It's very wide where your palm would grip and very narrow where your fingers go to click. If you like to use your middle finger to operate the wheel and ring finger for the right click, pass on this mouse.
I can't say my hands are too small, they are average, and if they were any bigger my fingers would be more cramped at the top end, any smaller and I wouldn't be able to wrap them around the bottom end.
The tracking feels weird, which is sypmtomatic of Phillip's Twin-Eye sensor. I didn't have a lot of tracking loss or dust issues like with a RAT7 (which I now own and will be replacing soon) but I always felt like I suffered accuracy loss, if you're serious about FPS and being accurate this will be an issue. I ran it with 400,800,1100 and 2000 DPI, and I used to run higher, it never felt right.