I've posted about my experience a few times but in a nutshell, I used the Marie Mongan book and CD (no classes as am overseas), and it worked wonderfully well for me.
I was able to stay relaxed, focused and calm through my labor which was just what I wanted and used visualisation (though not any of the methods in the book - with each contraction I just visualised blowing up a blue balloon and watching it float away as the contraction passed). I wasn't particularly fussed about not having pain relief but found that I didn't need it as I was in pain however it wasn't unbearable (at which point I would have asked for pain relief). It honestly was the most exhilarating thing I have ever done and I was high as a kite after DS arrived with all the endorphins!
I was very lucky that DS1 was an "optimal" birth for hypnobirthing, he was in a great position and I had a very quick labor (just under 5 hours from first twinge to babe in arms), along with very predictable contractions. I genuinely loved my labor and birth with him and could not wait to do it again.
I had some complications during pregnancy with DS2 which meant his heartrate needed to remain monitored during labor. I hadn't really had time to practise my hypnobirthing methods and ended up going into labor in the evening, so opted for an epidural so I could sleep through the night and was woken up by my OBGYN letting me know I was nearly 10cm and it was time to have a baby.
Both experiences were amazing and I'd do either all over again, although the hypnobirth requires a little more concentration 
Good luck, if you can use the hypnobirth methods, they are amazing to help you keep calm and focused during labor even if you do decide to opt for pain relief. Its the freedom from fear which is the main bonus.