My wife had been going for a few weeks to one of those booths where you get 15 minutes per session. She had felt the vibration plate machine toning her muscles in her legs, where she was trying to lose some weight, and felt more 'flexible'.
So, we decided to buy one as you can then do the excercises when you want and as often as you want.
I had looked at all the different one's about, and put my money on the Medicarn as it looked right and had the best HP motor.
The Medicarn was easily put together, my daughter (18) managed to do it before I got home from work as it had arrived mid afternoon.
My wife has said it definately helps with back pain when doing sit up excercises as she never managed to do them before as well as can feel it continuing to tone up her legs / thighs etc after only a few weeks.
The built in program routines have a wide variety of settings and there is also manual settings, the only slightly annoying thing for me is the beeping noise when pressing the buttons and when the program has finished!
We were afraid it wouldn't be as good as the ones in the toning booths, but seems to do the job.