Overall, I think Klobuchar and O'Rourke didn't have the nights that they might have wanted. Instead of positioning her self as the moderate rebutter to Warren and Sanders, Klobuchar sort of ceded ground. She didn't talk as much as Delaney (which might have been a moderator problem, to be honest), but when she did she didn't connect her legislative and systemic takes to the lives of voters. So, in some ways, she had a failure of communication, which isn't a great thing on a debate stage.
O'Rourke had a better night than the last debate where he was routed on key immigration messages by Castro. I think he does better when he's responding to another candidate, getting in the fray, not when he's doing his stump speech. So, he didn't hurt himself and that's good -- perhaps an underrated thing for him, given the critiques he's gotten lately.