Just as a kudos-to-banebots type post, we used a pair FP motors mated to the RS-550 gearboxes mated to a custom single-stage reduction gearbox to drive our arm up and down. The arm could lift the ball from the floor to the shooting position in about 3/4 second, and we never had a mechanical faliure all year.
However... one odd thing... the tube that makes up the body of the gearbox would turn a bit one way or the other as the torque flipped directions. Just kind of unnerving...
But, wow, for the price? Great!
-q