It looks like J&S copied Pitbull so if that's true they'd both be solid as a rock! The Pitbull lifts to 26" while the J&S only goes to 18" but the capacity is a little higher for J&S... could be the difference right there?
I have both the Pitbull and one of those Craftsman lifts that many members have. I've used both jacks on the Harley and the Dog, there's no comparison.
Bottom line, you get what you pay for!!!
Dennis
PS Just noticed the Pit has 4" wheels while the J&S has 3" wheels so I'd think the Pit would move easier with weight on it...