I just got the Cordless Mouseman Optical (USB connected reciever, 3 buttons+wheel) for about $70 at a Staples store near me. I had a corded Microsoft IntelliMouse Explorer ( USB connected, 4 buttons+wheel). I was perfectically fine with my Microsoft mouse however I really never got around to assigning shortcuts to the two side buttons. I have big hands and found it awkward trying to hang on to the mouse and click those buttons at the same time. Unfortunately that mouse was trashed when my nephew got the cord somehow wrapped around the chair and proceeded to backup/roll over the darn thing. I was going to buy a cheap 2 button+wheel mouse but ended up getting the cordless one instead. The thing was easier in, my opinion, to use than Microsoft's. I found it so easy to use that I have assigned functions to all the diferent keys (Logitech's Mouseware software takes you through it). I did have to adjust the mouse acceleration to high and the movement speed to the slowest it would go to get it to function right, I use my mouse in games and have to make long fast movement's which are hard for optical mice to track, but after doing this I have yet to see any hints/evidence of mis-tracking (jumpy mouse cursor). Another thing some friends of mine said that you cannot use the third (thumb) button in Quake III, this is partly true. I have found that to use the third button you must assign it a function that Quake recognizes, my third button is assigned to the 'Third mouse button' shortcut in MouseWare/Windows ME, and as such is recognized in Quake. In my rather long winded opinion, if I absolutely HAVE to get another mouse I will look for a Logitech, better prices and good compatibility (I have found this to be a pain when using Windows ME, but the Logitech mouse works without a problem in ME). I have no reason to use mice with more than 3 buttons+wheel, my overworked/underpaid hands would just soon find some cheap and easy mouse to grab onto, having said that this mouse changed my mind. Do yourself a favor, give it a try.