I actually have a small machine at home for this but I got it, and use it, more for rehab, which is the intended use of the one that I have.
Really works as far as taking away the pain and helping me back on my feet (literally and metaphorically) and just for that reason, I feel that it was worth the purchase.
I've never tried it to aid in strength training but I may look more into it and see how it goes for me!