[asid61]

+1 on slowness. 12mm/second means it takes 24 seconds to lift a single tote! However, it doesn't list any kind of gearing or anything, so I would contact them. It could just be the stock motor being slow.
You might want to try belts or chain if it's just for a simple lift, or try using just a versaplanetary if it's for rotating an arm. Much easier and lighter than leadscrews or other such actuators.