Trump's presence has been helpful to the republican cause in that he's shown that people will react positively if you set political correctness aside and just say what you think. In my opinion, he needed to do more than that last night - he needed to start offering specifics, to show that he has the ability to be a true statesman, but he left a lot of people questioning his ability to do so.
The candidates that impressed me the most with their performances last night were Huckabee, Cruz, and Christie. I think Huck was the strongest of the 'classic' Reagan-style conservatives. Christie is more moderate than I normally like, but when you consider how heavily democrat New Jersey is, I think it's to his credit that he can maintain his governorship. I also like his brashness & lack of concern for PC dialogue. Cruz is sharp as a razor, and despite his somewhat sanctimonious delivery, comes off as being very sincere.
I've always liked Kasich, going back to '94. There are qualities I like about everyone that was on that stage last night, and I would vote for any one of them before I'd vote for any of the 5 democrat hopefuls.