I have had an MM3 for a few years now. It has performed quite well. I have pulleys on mine that drive it at 220 rpm. It was driven originally by a 1/4 hp motor. With that it would chew right through barley malt, but tended to bog down on wheat malt. I swapped that for a 1/2 hp motor. Now I can just fill the hopper and come back when it is done.
I have seen posts favoring using a gear motor and direct drive to minimize stress on the bearings. Those motors get pricey in a hurry. I already had the conventional electric motors around, so all I had to buy were the pulleys, influencing my choice. I will be quite surprised if I ever put enough hours on it to wear the bushings enough to regret this choice.