I wonder if powering a mill with a drill causes more wear and tear on the rollers than hand cranking.
I've had a Barley Crusher for over 7 years, and I've probably put somewhere around 1,500 lbs. of grain through it (almost all of it with the hand crank).
I've experienced a stuck roller once or twice, but it wasn't anything that a bit of cleaning didn't fix, and the knurl on the rollers is still very much intact.
The JSP and Monster Mills look pretty nice though. If/when my Barley Crusher dies, I'll probably give one of those a try.