Several of my friends are reiki practitioners- and i've promised myself that i will do the course one day-but it is quite expensive. There also seems to be a bit of a mystery surrounding it unlike most of the other therapies. I believe there are certain symbols that the reiki master concentrates on (but I may be misguided here.)
However having had a reiki healing session- I found it very relaxing and calming. It is like a form of spiritual healing, or laying on of hands. Once you start to attune to what is going on you can feel the energy move, feel tingly etc. I have found it very good with headaches.
Again this is something that you might need on a regular basis and again depending on the therapist this could prove very expensive.