I really like it, and now that I have sanded several backs and sides see few minor issues of concern on the 10-20.
First, is the right front belt guide that can let a thin piece slip under and get stuck while the drum is churning and possibly digging a groove (that's another reason for a carrier board for thin stuff under 1/8th inch).
Second is the tracking, and tendency for the belt itself to drift right (after laboriously setting and resetting while spending enough time (more than 10-20 minutes) for the setting to take hold. This is a slow drift, and a few sides can be sanded before readjusting, BUT... I've read on amazon reviews that there is a fix -- loosen two lock screws located near the back RH side of the belt (going into the motor frame), and keep them loose. I haven't found those; and they're supposedly not connected to the adjustment levers.
Lastly, I haven't changed sandpaper yet, and the installed-from-factory 80-grit is course. It's good for dimensioning, but leaves grooves. For now, I'll try my ROS to sand out those small grooves and move up in steps to 220 or finer with it. But I'll soon see what all the grief about changing out sandpaper is like, because I'd like to use finer grits.
Also, I'm aware that the height adjustment treads wear out, as reported in Ken's posts. Probably a good investment against future failure.
Other than the Jet 10-20 is a worthy and work-saving machine.