I'm working on a new project and I can't figure out if I should be looking for stepper motors, or going for servos. I'm going to be driving a acme lead screw, essentially unloaded, to a position and then holding there. the acme screw has a 32 percent effiicency, so it shoul dbe self locking. It's my understanding that steppers only run into problems (losing steps) under high acceleration/speeds, and under great loads. Since the load is minimal, and the motor will be electoronically limited to about 250rpm, will an open loop stepper motor be sufficient to maintain my precision? do I have a good handle on what will make me lose steps and therefore precision?