Some of you mentioned that Razer mice is okay, but the truth is, there are way better options out there, as Razer mice sometimes have acceleration problems and bloaty firmware/drivers.
Mouse wise, Logitech, Mionix, Zowie, Finalmouse, and others are way ahead of the game, have very ergonomic shapes (depends on the person), and good firmware.
Of course, if you get it for free, that's awesome, and that's a whole other argument (I don't complain about things I get for free).
Therefore, I really cannot think of a single product of theirs that has a competitive edge over other options in today's market.