I know what you mean... I took the course. I had a wondeful instructor, so the whole course made sense to me. At first I also hated Mongan's voice. I found it annoying. But I forced myself to listen to it daily (to practice - I hope you are doing it anyway) and in a short time I began to actually like it. One month later (close to my due date) I did not need to listen to the tape during my hospital labor - I had the dang script memorized in my head. I just focused on the memories of feelings it brought me. Total relaxation. I felt no pain for my 20 hour labor.

My painfree birth story is on this thread:
Tell me more about Hypnobirthing
Anyway, this is an easy dilemna.
I'd choose the
HypnoBabies Supplemental program.

Kerry Tuschoff (sp?) created it using master hypnotist Gerald Kein's Painless Childbirth Techniques. It's a complete course and VERY AFFORDABLE.
Here Kerry explains the differences between HypnoBabies & HypnoBirthing.
Kerry (a former 14 ? yr childbirth educator, now exclusively focusing on HypnoBabies classes) has a yahoogroup just for her moms and is very generous with extra scripts. She is a regular poster on that Babycenter board.
I've seen the Hypbirth website. Nice photo of Amanda on the front page at 9 cm. Very calm. That was me at 9cm too (without Hypbirth!). I was calmly brushing my teeth during transition over the hospital bathroom (ick) sink.
The creator of Hypbirth is a Doula. That is her primary profession. (She was an experienced Hypnotherapist - but only 5 years. She is not a Master Hypnotherapist.) I am always skeptical of people who want to "do-it-all." It appears that she created this course using the best of various other courses. That is fine.
On her bio it says that as a Doula she observed which Hypnosis techniques worked and which didn't. Frankly I need more information. Did she teach the hypnosis course herself to her clients? (I think that is a disservice to clients. Stick to what you are good at.) If so, that would explain why it didn't work for (some/all of) her clients. So she tweaked and tweaked and tah-dah.
The Doula I hired 3.5 yrs ago was new to HypnoBirthing. She started to teach it to her clients. It was an awful experience. She didn't give me the book. She just gave me 2 tapes (rainbow relaxation and Birthing affirmations) of her own lousy

recorded voice. It was an extremely watered down version of the course (if you can even call it that.) I was fortunate to have found a local, real HypnoBirthing practioner. She happened to be new to
teaching the entire HypnoBirthing course, the way it was meant to, but she was a Master Hypnotist for years. When she heard what my Doula was doing, she was horrified.

That Doula is still offering HypnoBirthing under her services.

This experience colors my opinions of Doulas offering Hypnobirthing.
BTW, I fired my Doula and did not need a doula to help me cope with contractions, because I was doing great! Though at pushing, it would have been nice. Someone to offer other choices to the Pitocin we opted for and to help hold me in supported squat so I wouldn't tear.
If other moms on the Hypbirth site say it's good, that's great. I'm sure it works. But Hypnobabies is far less expensive. That makes my decision a whole lot easier.
As far as specifically targeting Endorphins... e-mail Kerry and ask her about that. Whichever program you use, if you are DEEPLY relaxed, then you WILL feel the endorphins.
Kerry is careful not to promise that birth with be painfree. For the majority it can be. But for some (who are too stressed out going in, unable to trust and relax - or who have not practiced) there will be degrees of pain.
So eventhough the Hypbirth "sounds better" keep that in mind. It's all about $ ka-ching $ making a sale.
The majority of my Hypnobirthing practioners students had first time 6 hour labors. (I credit that to the fact that my practioner was a Master Hypnotist.) Many of her clients felt endorphins BETWEEN EVERY Contraction!!! My labor was 18 hours - I know why - and I only felt endorphins when I was in the shower - even more deeply relaxed.
My .02 cents.