I took a HypnoBirthing class during my first pregnancy, sat through a Bradley series between pregnancies and did the Hypnobabies Home Study for my second and third births. Clearly everyone has different needs when it comes to preparing for birth, so none of them are one-size-fits-all, and all have something to offer the right person. It is up to the individual to research all the options and decide which one best fits her personal requirements.
That said, I found Hypnobabies to be the most complete and useful of the three classes mentioned. It combines a complete natural childbirth education that included everything I heard in Bradley, with deep medical-grade self-hypnosis skills that far surpassed the basic guided relaxation in HypnoBirthing. Honestly, I know people often try to compare Hypnobabies and HypnoBirthing because they both happen to have "hypno" in their names, but they are far more different than they are similar. Hypnobabies teaches deep self-hypnosis skills utilizing several scripts filled with powerful post-hypnotic suggestions that build on the previous one to create an entire toolbox of highly effective relaxation/hypnosis cues that can be used by the mother or with the help of her birthing team. HypnoBirthing uses guided relaxation, visualization and one general chakra clearing CD without creating any real hypnosis skills. I think HypnoBirthing can be a nice choice for a mom who is well-informed about NCB and has already accomplished a few unmedicated births, but is looking for a little extra relaxation. But I don't think it is generally a good choice for a FTM who is looking for deeper skills or who needs any childbirth information. It was fine for my very early birthing, but when things got intense, HypnoBirthing just had nothing left to give me, and the lack of information about birth led to me having some avoidable complications as well.
What I liked about Hypnobabies was that it combined excellent natural childbirth information with the self-hypnosis information, so that it was clear how best to utilize the information and skills together to maximize their effectiveness in achieving a safe and comfortable birth. Hypnobabies goes way beyond what someone would get out of combining a Bradley class and HypnoBirthing, because it is specifically written to intermesh the strongpoints of information and relaxation into one extremely effective method. And it really gives so many clear and exact suggestions for how to use everything that it teaches, so there is none of the, "Ok, that's nice in theory, but how do I *DO* that?" concerns that I and my classmates had coming out of the HypnoBirthing class.