I've owned the "quarter folding" rebounder by ReboundAir for two years. Its very stable and has performed flawlessly. Because I have bad knees, I cannot jog outside. So using the rebounder is the next best type of aerobic exercise for me. Its very comfortable to use and easy on the knees.
I use it to jog in place, as opposed to jumping on it. I weight 185, use it about 2 hours a week, and no broken springs yet. I would easily buy another one if need be and highly recommend it.
This review is for the "quarter folding" ReboundAir rebounder, which from the reviews I've read, is considered the most stable one they make. I don't have experience with their other models, but I'd pay the extra and get the quarter folder, as the company recommends it as the most stable, and my experience is that it is very stable.