I bought the MX mouse 2weeks ago. I can assure you that it is god dam awesome mouse because the scroll runs really smooth compare to rubber wheel. the battery last 18 days fully charged. I strongly recommend you recharge the mouse every time you aren't using it.
This mouse has 2 types of scroll features:
a/ the click-click scroll enable user to scroll like traditional rubber mouse that has high resistance.
b/ the free-spin scroll enables user to scroll smoothly without the high resistance feeling when you roll the wheel.
The aluminum wheel is very well designed. I bought the ernermax aluminum keyboard to match this mouse. The enermax keyboard is much cheaper than the new logitech aluminum version, which will be on sale soon.