What it all comes down to is "Do you feel you can trust the individual specialist?" whatever field he or she was trained in.
If at all possible ask your friends who they know that has been to that individual and what their results were. Word of mouth is by far the best way to find out who the good ones are.
I don't care how impressive a person's creditenials (sp?) are, if they aren't effective at what they do, I don't want to waste my time.
Sometimes too there are people who may have less book learning, but more 'healing touch' who just have a knack for it...whatever the discipline.