A long time ago I knew a physical therapy clinic that used the G5 massager.   It’s been around a long time.  They also have smaller hand held versions now. 

http://g5.com/products/therassist/

I would think it really depends upon what  your looking to accomplish.  Any properly used tool can make the massage therapists job easier.  However there are some things a physical human can do that no machine can duplicate.  

There aren't any massage machines that have built in sensors as of yet.  They can't determine if they are on blood vessels, nerve clusters, bone or tight muscle.  All to often tight muscle can feel like bone if it's tight enough.  All that gives the muscle away is experience and intuition.  

Machines also can't transmit sensations through touch.  Many clients can sense what a therapist is feeling through the sensations of touch from the therapist.  These feelings and thoughts that are transmitted can enhance or destroy the massage experience.

With those two considerations I  have to vote in favor of a real massage experience with a real trained massage therapist.  A machine, might be able to fix your problems.  It however can't provide the complete experience by it's self.