Check out their site. They will give you all the information you need. We have had one for years and it's held up nice. My mom had one with the stabilizer bar because she doesn't get crazy on it. Just bouncing and not taking her feet off the fabric. The kids of course are a different story.
If you want quality, go for the Needak, in my opinion. The have books and tapes also that will explain how to do the exercises. It doesn't take much to get a work out.