I'll add one additional point. What made parts of hypnobirthing work well for me was precisely that I never look at it as this magical, cure all, nirvana like solution that would make labour pain free.
It is very very crucial I think to go in prepared, with an open mind, and particularly aware that the best way you can use hypnobirthing is to strip it of the ample rhetoric of "your birth will be like a gliding ballet performance, beautiful and musical" - take that out, bring it down to its core - breathing techniques, being present, and then walk in with adequate information about all possibilities and walk on with confidence.
If I had for a moment believed that labour would be pain free, that as a "true" hypnobirth ear I shouldn't even mention the word pain, or worse - chastise those women who had had difficult births - then I would have been shocked.
The hypnobirthing community can be full of some very judgmental people, and I had, before giving birth spoken out against this on a Facebook group where a group of smug hypnobirthing were chastising a lady who had ahad a difficult birth. I said my mind to the group admin and left the group.
And then still went on to use hypnobirthing successfully in my own birth. But like I said - it's best used, absolutely stripped of all it's rhetoric, stripped down to what you choose to use out of it. And an open and aware mind is your best friend as you walk into childbirth.