I use a razor naga, it rules, but the main gripe i hear from other people is that its too small for there hands. TBH my hands are a bit big for it but it just means less moving my thumb around while hitting the side buttons.
Cant comment on other Mice since all i use are Naga's
Best thing to do, which pisses off store employees, is carefully undo the packaging of the mouse you want to look at inside the store and play with it, see if you like it. Usually an employee will comeover and ask you wth are you doing, but i just tell them "If I'm about to pay sixty dollars for a mouse, im testing it out." At that point they will just watch you to make sure that if you dont want it, that you put it back in the box properly and not mess it up