I bought this in a hurry from a store to overcome a short term mouse crisis - it was basically all they had to offer. I'm now looking for something else that returns my beloved scroll wheel functionality and doesn't feel like I'm moving a tank around the table.

Very accurate once you've mastered the double DPi movement technique. I use this mouse for image editing in cs3 and for gaming and it is without doubt a huge improvement over any LED mouse.
Energizer batteries last a good 3-4 months with daily usage so running costs are cheap.
Intellipoint Driver 6.1 is definately the one to use. 5.5 doesn't work with vista.
All in all a solid mouse and is actually nicer to use than it's more exspensive 6000 brother (My Wife uses that).
Highly recommended but be prepared for a whole day of learning to use it. 9/10 Mostly because of the daft right button.