Summary: It's a really comfortable mouse and the buttons work great all the time. Good speed, nice movement, everything great, until a few months ago - almost exactly a year since I started using it - THE SCROLL WHEEL DIED. It started jumping down when I scrolled up. 3 or 4 steps up, 1 down. Today I can't event graze the wheel because it's like giving it 3 full turns. It goes crazy.
Summary: This mouse did end up failing after two years due to a faulty scroll wheel, but Corsair replaced it, no questions asked, out of warranty with the M95 mouse. Corsair takes care of its customers, and I feel a lot better using a product they stand behind.
Summary: I'm writing this review after two years of owning the M90. I had bought it for use with World of Warcraft and it did its job beautifully, but I did have some problems which I will go into. The aesthetics of the mouse are also great. Vibrant lighting effects (especially love the back-lit Corsair logo at the back of the mouse.). The tactile feel of the mouse is smooth and soft thanks to some kind of coating, maybe rubberized?
Summary: Overall, the mouse is excellent. It is comfortable, beautiful, and solid. I especially enjoy the layout of the alternative buttons. There is a small learning curve (as there would be with any multi-button mouse), but once you get it programmed how you like it, your action-packed MMO play becomes much more efficient.
Summary: Bought this mouse because I've always had good experiences with Corsair products. SO glad I did. Primarily used for gaming (mainly Dota 2). Mouse has a nice, heavy weight to it, which I've always preferred to lighter designs. Surfaces are all very durable and stand up well to heavy use, layout feels very natural, and lighting looks really sharp.
Summary: I am a palm grip user. I have this mouse a few months to get used to. To me using this mouse is life getting hit with bricks in the hand. After a long session my hand was always sore. Also, the side buttons seem awkwardly placed and the software want that great.