I travel through Amsterdam Schiphol regularly where all scanners are the new CT design. Security does not seem to be any quicker because although you can load your tray quickly and leave everything in your bag (including larger bottles of water), the trays are scrutinised more and it seems more trays are physically checked. So the delay is waiting with your tray to get it onto the conveyor belt - the staff are very fair and ensure each passenger is dealt with in turn. In my experience not a huge step forward.