I love hypnobirthing!
I was planning a home birth but, due to having meconium in my waters when they broke, ended up being transferred to hospital for monitoring.
Despite this big change in plans, being immobile on a monitor, and ending up being augmented with a drip to speed things up, and the baby being back to back, I got to fully dilated without the need for any other pain relief. It was a very calm labour, my midwife was very impressed with how well the techniques allowed me to cope (I just hummed and breathed through contractions) and assumed I must naturally have a high pain threshold (I don't!). I ended up with an emergency section at that point, but walked calmly down to theatre, still humming and 'surge breathing' through contractions.
I would highly reccommend it.
I took classes and think you do have to put the time into practicing the techniques, whether you do classes or just read the book and get the CD. I'd also say your birth partner needs to be on board. Mine agreed to do it for me, thinking it would be airy fairy rubbish, but once he had read up on it (and how the science of the theory works) then he totally came on board and that made all the difference when we were in a difficult situation.
I've done a refresher course this time, and I'm looking forward to a second calm and pain free labour, hopefully at home and in water this time, but I have total confidence in it whatever the circumstances.
My home birth midwife rates it highly too, but says you need to put the time in.