I've had good luck with the Powermaster XS Torque starters as well.  However, one thing I don't like about them is that the drive gears don't engage the full width of the flywheel teeth, at least on the engines I've checked it on.  They go about 2/3 of the way in.  They still work pretty well though, and have never given me any significant trouble.
Because of the tooth engagement issue I've also bought and tried out a Robb McC starter.  I like the design better because you can buy them with the nose support for the shaft, just like the stockers have.  They are expensive, though...