We are in the market for a new top load washer. There seem to be a couple different style agitators available. Some have something that looks like a "Screw" and they have kind of turn and stop, turn and stop action. Suppose to pull the cloths to the bottom of the drum or something like that. Others are just the normal looking round agitator. Just goes back and forth. Which is better? Salesman are no help... Thanks, Rick