I have a small Trioliet vertical mixer (single screw). Works great and is extremely simple to service. I had a Steiner tumble mixer before and it was a nightmare to maintain. Too many chains, belts, and bearings in the horizontal mixers. The vertical mixers have a pto and a gearbox. Pretty simple.

The Trioliet cost $16,000 about 3 years ago. The Steiner cost $15,000 back in 1988.

http://www.trioliet.com