I agree with all of the above.
Having just completed a swedish massage course myself i have seen some BAD masseurres and some EXCELLENT Masseurres.... and i think the key to it is experience. If you're looking for a really good one and experiencing problems with your back, the best place to go is a physiotherapist... they are taught exactly the right moves to correct issues rather than just the basic moves of a massage. If not, try and find a massage specialist, not just someone in a general salon...
Additionally, you can try and locate a sports masseusse....