The elevator. That is an unholy mess. It lets you upstairs if you use your keycard. But you have to listen for the click in the ceiling for it to 'take' (inserting card at least 3 times prior). Then if someone else has already used their card it may work without, but you can't be sure, so you end up with five confused people in the elevator inserting their cards and hoping for good luck. With several people and several floors, this is mass confusion. Get rid of the damn keycard reader in the elevators.
Service, lobby, cleanliness, wifi (used phone, not a computer). Bahnhof noise not a factor. Breakfast is very good. Room safe. Location. Bus pass. And most of all: THE GYM ACCESS!
Room is plain, but very very clean.