The mouse feels comfortable to use, it is quite big so those with small hands may find it too big, underneath are 3 protrusions that lift the mouse a few mm off the mouse mat, this gives it a nice smooth gliding feel.
The scroll wheel has a nice tactile feel to it and scrolling is also smooth, The scroll wheel lights up which is a cool feature to have purely for aesthetic reasons.
I did not install the driver on my mac just plugged it in, the scroll wheel button is assigned to dashboard and the side button expose, but I never use the extra buttons.
Overall very impressed with the build quality, definitely a keeper.
A tip I've learned to reduce the pain caused by RSI is to use a different mouse every few months, I own 3 mice an apple mighty mouse a Microsoft Intellmouse and this one I just alternate between them.