I have been to Sansuk many times and it never fails. My therapist, Mam, was superb. She is extremely experienced and knows what she is doing.
My only suggestion is to have slightly thicker towels on the bed and the hole into which you place your head when lying face down. It's not at all uncomfortable, far from it, but maybe a towelling cover for your face would be better. Overall though, 5 stars!
I went in with some back pain that sprung up, and not having had a Thai massage I was unsure what to expect. It was great. My masseuse really worked out my knots, was very friendly and always checking in on me. Lovely choice of oils and came out refreshed with my back feeling soo much looser. Will definitely be returning!