Okay, here's my observations:
You can almost tell when Bush is slipping into campaign autopilot -- that said, he was pretty gutless and unassured the entire debate. He wilts terribly under pressure -- even going so far to agree with Huckabee on Kim Davis! But his statement of support was so noncommittal and conditional I doubt he's going to sway voters either way. The high five with Trump made him look like a dweeb, especially after his righteous indignation earlier on in the debate.
I mentioned that Fiorina is theatrical a few posts ago, but her mannerisms had a hard, sneering edge to them. I can understand her disgust for Trump, but she seemed to have issues with other candidates as well. Perhaps it's just a reflection of her positions, because she seemed more of a pure ideologue than everyone except Huckabee and Cruz. Was she like this when she ran for Senate in California?
It's hard to tell where Carson's going to go from this point, because he has these extreme issues but he's been so soft spoken and unconfrontational during these debates. He's so non-threatening to Trump that he's the only candidate who hasn't activated Trump's snark blast.
Rubio isn't as out front with the religious stuff as much as Huckabee is, but he definitely puts it out there, and the crowd was feeling it. I think he's trying to be folksy in the same way Biden is but his family anecdotes are well worn territory.
Walker took an orthodox position on every issue and amusingly referred to Trump's criticism as liberal tactics, but he's a total non-entity on the stage. No personality.
Cruz was slinging red meat everywhere.
Christie politicked all over the place and had another chance to talk about 9/11. Amusingly, he was plugging a drug law that came from his "crazy liberal" legislature.
Unlike the rest of the field, Paul seemed to relish his contrarian stance on most of the issues presented to him. He's probably closer to Trump in more ways than he'd care to admit.
Kasich, again, took a relatively moderate position on most issues and had a fairly logical response to the Iran deal.
Huckabee was vile, and never seriously countered.
I think Trump will stay in the lead, with gains by Fiorina, Rubio, and maybe, Cruz. Bush will wallow on with the same core of voters, and I'm struggling to imagine who Carson's performance would please.