Hoi, I`ve had the mouse for 1 month now, and my thoughts are: If you have a "big" rounded thumb, it might not be pleasant holding the mouse, as your thumb might touch the bump for the mouse controls. Secundo, when i play first person shooters, the mouse occasionaly moves up or down. This means that if your running staight forward, you will find yourself still running forwards with your head looking straight down. Experienced in Half-Life 2 and Unreal Tournament 99. Might be my desk, but I doubt it as is is wood and had NO problems with optical mice before (MX510, Logitech MX, MS scroll mouse, explorer mouse.) Thirdo, in Half-life 2, the primary (left) mouse button occasionaly gets "stuck", and the weapon fires in full auto mode. I havent been able to determine if the button actually sticks, or if it is a game problem. As for mouse speed, I have no complaints. You can play very quickly and probably wont notice any lag as earlier wireless mice. The lithium-ion battery last longer. I've played maybe 4-5 hours/day for 1 month and the battery meter LEDs were still 1/3 full. Charging time on the cradle is fast. ...but you have to try it see if you like the "feel". Hope this helps.