Who publishes a Bungie game is irrelevant. You fear a rush job? They were forced to rush H2 and they delivered pretty excellently. You fear Activision getting their hands all over the game? Bungie isn't dumb. They didn't rush into a deal that will handcuff them creatively.
Bungie has pretty much done everything a developer can possibly do to service fans and make quality games under the conditions they have. And you think that now that they have more control, money and resources than perhaps ever before, they are going to screw it up?
Rest easy, friends. The only hitch I could possibly see is them learning to code for PS3. I'm sure they will bring in experienced teams to help, and Activision has clearly published lots of PS3 games and can help there.
People over-reacted when things like DMC4 and RE5 and FFXIII came to 360, and there will be those that over-react when Bungie appears on PS3. But it's all over-reaction. The day of the non-first party devs going exclusive are pretty much over. And fronting all the costs of games of Halo's magnitude, which their new IP seems to be in terms of scope (at least!) is dangerous. They needed a partner with deep wallets.
People need to get a grip. Doesn't matter much. Probably won't be out until 2012 at the earliest, and likely 2013. That's a long time to keep one's panties in a bunch.