Well we bought one of these devices anyway, mainly due to the low price compared to repeated physio treatments.
It has been used on a series of small niggling injuries within my training group with some success. After this I reccomended my dad purchase one of the cheap ones of ebay for help with his achilles problems from jogging. He says he no longer has pain the day after going for runs and can now run more often with out pain. It may just be a placebo, but my dad is a very sceptical guy, and does it really matter?
Admittedly these devices don’t seem to as good as a proper ultrasound in the hands of a trained proffesional, but the do seem to do something good and we don’t regret our purchases.