I've used 2 types:
- A motorized/hydraulic 1-man unit, with outriggers. While not as stable as a larger unit, I was about 50+ up in a church and the sway of the basket was about 2' side to side. I didn't fear that it would fall over, but it sure made my stomach turn!
- An air powered one-man unit. This thing was actually pretty fun, I think it had a 26' working height. They are meant to be used with CO2 bottles, but we used an air compressor. Really quiet and fast, when you hit the lever, you'd hear almost nothing.This one was very beefy and more stable than the electric unit.
They take some work to setup, but they are safe. Often, it's the only thing you can get in the door. Always use the outriggers, you don't want to fall over in one of these.
Mike