+ Optimum ergonomics (also for large hands)
+ Weight
+ Precision
+ Good pressure points
+/- Mouse wheel is me personally too light, always in mm schritten.Wobei in certain applications this can so have its advantages.
Installation has also worked wonderfully with Win7.
Edit 11/19/2014
Three years ago and there are still the org. Batteries in the mouse. Daily use of about 5h.