I did the Buteyko course in Sept 06, and highly recommend it.
BEFORE BUTEYKO: I have suffered from Asthma since I was a child and have been hospitalised several times. Before the course, I was using my Bricanyl inhaler 3 times a day, and my doctor recommended I change to a stronger drug, which I didn't feel good about. I was also struggling with allergies, frequently using Flixonase and tried several other over the counter meds to try and cure it. The medications were only helping slightly, so my energy levels were down. I was so unfit, I couldn't walk up small hills without stopping - not what you'd expect when you're in your mid thirties. Apparently, I also snored all through the night.
My wife embarked on a crusade to cure me. We visited a specialist who was able to get me off the couch and exercising again, through the use of 5 different medications, including, steroids, asthma drugs and antihistamines. This was fantastic for a while, but after the steroids ran out, I was back to square one. I had a second prescription of everything a few months later to 'kickstart' my system, but again, it wasn't lasting.
BUTEYKO COURSE: We found Buteyko on the Internet and decided to go to the introductory session. The information made sense so I decided to do the five day course. Glenn did a good job of explaining everything, the challenge is when you leave the course and you need to keep up the breathing exercises 3-4 times a day, a total of about 1.5 hours a day. I could see slight improvements right away, but it wasn't until about 6 weeks that I began to feel much much better. I was back swimming & cycling and stopped using Bricanyl or the antihistamines.
I stopped doing the exercises after 5 months, and the benefits remained. If I notice my breathing slipping back, I might do them again for a few days to get back on track. I have used my Bricanyl inhaler probably 3 times a year, and a much milder antihistamine when pollen levels are high. I don't snore anymore either.
I highly recommend Buteyko, it has changed my life.