Not sure if you're still looking for an opinion, but I might offer a unique perspective. I am currently playing in a PF game, and it is going okay. It wasn't the game I would have chosen but my current gaming group agreed to run a PF game first, but I can't help but see all the things HM does...
I have yet to be dissapointed by Kenzerco's products and the HoB is no exception. It is on the level of quality that Aces & Eights is well know and rewarded for. The other upcoming Advanced Hackmaster products should be just as good.
I'm stoked! Hoody Hoo!
Seems to me that such an issue really revolves around people preferring one style/edition over another. If it we were me and the world were perfect, then the owners of the name would support all the editions.
Unrealistic, I know, but I see no other way to satisfy 90% of the D&D crowd...