This is in regards to the auto-throttle - the throttle levers jump back and forth when climbing in FLCH mode (quickly, very unrealistic)
In regards to the auto-throttle and VS mode - when descending using VS mode and using SPD mode when reducing the speed to be maintained during the descend the auto-throttle can not maintain idle thrust - and jumps instantly to max thrust (and back to idle vice versa...) never managing to reduce the thrust to maintain the desired airspeed.