The new flywheel scrollwheel is a step backwards IMO.

My MX Revolution can be software set to be freewheel or clicky. The default is to be clicky until it reaches a certain speed and then it will switch over into freewheel mode. Once it stops then its back to clicky.

I actually like this feature because it is clicky for precise scrolling but if I want to scroll through something fast I can just spin the wheel and go into freewheel mode.

I recently ordered some spare MX Revolutions because they've discontinued this model and replaced it with the Performance Mouse MX which has the scrollwheel that Tony mentions and its missing the side wheel/button.