The new silicone coverings on the Actions Ring button and the right lower side of the mouse are very slippery in my hand. It is difficult to pick the mouse up. The curvature of the left side under the thumb buttons has changes and also contributes to the difficulty in picking up the mouse. Hopefully as it ages, these issues will improve.

Overall, the mouse is improved with the additional thumb button (although the click is much louder than the other two), and the Actions Ring button now using the natural opposing thumb action of the human hand.