TL;DR, short summary:
I like the mouse, the coating is the traditionally easy to smear and spotty Mionix coating, unfortunately. As it doesn't affect functionality I will focus on the technical aspects. After a few hours even my dry hands smeared the mouse quite thoroughly. When will Mionix change that coating!?
The mouses glides very well, is very light and the grip nice for palm and claw. Fingertip might find it a bit too front heavy. Also be careful if you have long fingers or very large hands, my pinkie is already rubbing the mousemat. The thumb buttons are very nice, but by button shape and position so close together that pressing the forward one is likely to hit the back button, too.
Tracking is on the smooth side of things, like everything on the mouse. The mousewheel is very silent for me and perhaps a bit too soft. I would like all that a bit more snappy, the PMW3366 or at least Logitechs implementation has an edge here, I also like the wheel of the G303 a damn lot.
The shape is very easy to fall in love with and get accustomed to, so it's a real alternative for players who cannot get used to the G303 shape. The mouse glides also very well, better than the G303 IMO.
What surprised me was the rubber inlay, it puts Razer's to shame as it is a perfect fit and feels absolutely great. And I actually hate rubber in general!
Software/Firmware woe: Would like 2 dpi steps instead of 3, cannot change that, unfortunately.
All in all this mouse is well worth a try. For Mionix Users, it's not really a massive upgrade over the Avior, which has IMO a better and a little more rigid wheel in general.