I had a Hoover 2-tub impeller machine many years ago, and the impeller, mounted on the side, turned continuously in one direction. It tangled clothes without mercy-I could have gone into business making rope. Don't know about the ones with the impeller in the bottom, though.
I use to have a Panasonic twintub and the impeller was at the bottom , it washed in both directions, I sure do miss that machine, I went off to college and it was sent to the crusher while I was in school, I have been searching for one with no luck...
I rented in Australia and we had a machine the same as this but larger capacity. Having had Hoovermatics for years and knowing that they are very prone to tangling I was a bit wary of it but unlike the Hoovermatics, they do reverse and I was always pleased with the results. I would have one now if I could as the capacity seemed emormous without a tradiional agitator in the tub.
Someone paid a decent price for the set. They probably will only use the dryer a few times unless they can use it on a patio or balcony as there is no method of venting. It blows air through the drum from the back and out the front of the machine below the door.