Summary: This is, in my opinion of course, the best mouse there is. I now use a tablet as a mouse only due to wrist issues, but otherwise I'd still be using it. Downside is that I needed to purchase a new one every year or so; I'm a very heavy computer user.
Summary: Dont forget to feed this mouse it performed brilliantly for me until I went away for a weekend, I forgot to feed it and found it dead upon my arrival back home. I have now replaced it with the same model and all is well!
Summary: When my Microsoft Sidewinder X8 packed up just outside of the warranty, I was in the market for a new mouse. I was tempted to go for the X5 but then remembered how nice my old intellimouse was (with the chunky grey and see-through plastic design), and saw that Microsoft now did this slightly sleeker version. It's a fairly no-frills mouse for gaming, but then, that's all you need.
Summary: In short: This is the mouse you buy if you're looking for accuracy and response, but either dislike or feel apathetic to style or a plethora of gadgetry. If you're looking for a gaming mouse that has more than four buttons: go somewhere else. If you're looking for a gaming mouse whose aesthetics key in with your glowing keyboard: go somewhere else.
Summary: The reputation of this mouse truly preceeds itself, as it is really quite a legendary mouse, which many professional counter strike (1.6 and source) players used to and still use. The sensor of this mouse cannot be faulted at all, tracking perfectly on the usual surfaces (cloth/hardpad).