Of the new guys, Brad seemed the most nervous. There were definitely moments were you could tell "Oh right, he was in RATM" by how he went with brute force instead...well imitating JC. He doesn't imitate JC, at all. I don't know if I'm explaining that right, but I'm tired because I too, worked all day and waited in line to be in front.
Jimmy = grace, Brad = SMASH HARD. No judgement yet.
Mark, on the other hand, seemed completely focused on what he was doing. He didn't have a mic, so he didn't say anything. In fact, he barely looked up. Musically, he fit in perfectly and he did move around and get into the songs. It feels like maybe Mark had more time to prepare maybe? Anyway, he was great I thought. I already liked him from The Killers though.
Sorry for rambling. Just wanted to get my initial thoughts out.