Very affective
I wish half stars were available because this isn't quite 5 star but, it's better than 4.  It is very powerful and really kneads the muscles and knots in my neck, shoulders and lower back.  In some places it's a bit tricky to get it right where you need it but, with a some maneuvering it can be done. It can be painful until you get the hang of the pressure you need but, it is definitely effective.  Minus the half star because I think heat would loosen my muscles better and this does not get hot enough.  When wearing a cotton t-shirt I can feel some warmth.  Just not enough for me.  Wearing anything thicker results in a relaxing muscle message but no heat.  I haven't tried it on bare skin.
Rating: 5 stars