I love Alexander Technique. I think there's a lot of merit to it if you're an actor, in some sort art, or you just have to use your body in order to make a living. I took some classes in it as a part of a conservatory-style acting class I was in, and I found the whole thing beneficial.
As you go through life, you learn to hold tension in really random places in your body. It's nice to take a good look at the way you move and live and get rid of any excess tension that you don't need. Then, you won't be as tired at night, and more energized in the morning. My teacher and some others have told me that they're much happier after going through some Alexander Tech, and they all seem to recommend it highly.