The screen is bigger, it has a row of Extra key (answer / end, menu and back + a trackpad).
These new keys are for users Q10 somewhat disturbing (redondandes with tactils shortcuts OS 10).
By cons, for those who could not go to Q10, the fact of finding the "classic" buttons will move to the new OS (which is better than the old Verily generations).
Personally I regret the transition to an IPS screen instead of amoled, and loss of the micro HDMI port.