The one thing I don't like about it, and I am talking about the intellimouse explorer 2.0 is that mouse wheel is very very sensitive.
the mouse itself is alot more sensitive and thats fantastic. it zips around, makes me twice as good as CS.
But if I use the mousewheel to switch weapons it can take me a couple of seconds, which is a pain in the arse as
a) I might have a knife out and be trying to flick it uselessly onto my colt
b) I buy a colt and need to switch to a knife, as you run faster with a knife - fumbling means I lose a couple of all crucial steps.