Favorite mouse shape (owned a G Pro since release). The mouse clicks are a bit heavier than the pro, the middle mouse click is lighter with scroll steps being more defined, and the side buttons have a small increase in travel. The wireless connection also appears to be just as good as the wired on the pro (using the range extender set at the back of my desk). The addition of another mouse foot on the back center of the mouse is also a nice touch. Definitely use lithium batteries if you buy this mouse! They're lighter and last longer, although a bit more expensive than alkaline batteries.
-1 star because there is a definite sensor rattle when I shake the mouse, something my G Pro didn't have. I can live with it if it means getting rid of the wire though. (this is something that I think will depend on luck of the draw, review units did not have this rattle afaik)