As objectively as I can be. (remembering this was not about issues - only style)
My grades:
Christie - F (Expect him to not make the cut next time)
Rubio - D- (Polished speaker, but didn't bring much)
Carson - B (Inexperienced in politics, but remained calm and above the fray. Expect him to get a bump)
Walker - D- (Totally forgettable. If they want a record, Kasich looked much better.)
Trump - B- (Some ups, some downs, but survived pretty much unscathed. Probably the best performance he could have hoped for.)
Bush - C (Just boring. But probably kept his donors on board, which had to be his goal.)
Huck B- (Started slow, but appeared genuine. Got a few laughs)
Cruz D (FOX wasn't very kind to him, which may help him, but he appeared too scripted. see Rubio)
Paul C (Definitely the most contentious - Had extreme ups and extreme downs. Didn't appear Presidential, but he may have just been wanting attention. Positive or negative)
Kasich B+ (Maintained composure. Mentioned his record about a million times - with no rebuttals to it. Seemed very at ease. Expect him to get a bump.)
Overall, I think the biggest loser was FOX. It was a horrible "debate". No candidate stood out. If this was an "introduction" to the field of candidates, Kasich probably did the best and Christie the worst. If this was about getting headlines and attention, Trump did the best with Paul and Christie coming in close second.