Excellent
Probably the best gaming mouse I've ever used. Although it is not as comfortable as the Razer DeathAdder due to its ambidextrous design, it definitely has a nicer feel to it. This mouse is definitely worth the price, but if you aren't that serious about gaming, there are cheaper mice out there.
Comfortable
-Steel Series Engine easy to use
-Tons of customization settings
-Looks great
-Thumb buttons on both sides; I don't mind the thumb buttons on the left side (I'm right handed) and I understand the mouse is ambidextrous, but the buttons on the right side drive me nuts
-Costly