Haley has been impressive, the person I'd choose out of the bunch if only considering this debate
Vivek is charismatic in a similar sense that Trump was - meaning repulsive to a lot of people - but others seem to love it. He also seems to understand that today's GOP doesn't really care about fiscal conservatism, they care about the dark days and cultural war with the Democrats. Probably wins the debate in the modern era of speaking time and entertainment.
Christie is a let down relative to his rebate reputation.
Ron seems to be saying the right things for his base, but is very awkward, so much cringe. Who knows which he'll be more memorable.
Scott pretty meh.
Pence has been aggressive but I just don't think his message resonates with where the GOP is today.
Asa, meh, I wish he was more effective
Burgum also meh, certainly not a natural, although doesn't seem crazy or a lunatic