We have had a lot of great thai massages when in Thailand. Relax Centrum in Prague is the best we have ever had.
Their skills, precision, and strength is superior. We had to come back for a massage the 2 hours before the taxi was leaving for the airport, it was that good.
If you only have a weekend in Prague, this is still where I would ensure to plan for a 2 x 2 hours visit. You can literally feel that the energy levels in your body has been unlocked, it's the most important place to visit when in Prague.