I use a Pittsburgh Jack. Has served me well for both the scout and roadmaster. The only drawback is that the strap down points are on the base, so whenever you adjust the height, the strap has to be adjusted. It's usually not a problem to stabilize the bike with one hand and adjust the Jack with the other though.
My strap is a little short, so I run it between the seat and frame and then back through the top of the engine. This works well for short quick jobs, but if I'm getting more involved, I remove the seat for more stability and two hold points on the frame.