I'd say 7.5. He looked comfortable, at ease - almost like he realizes this is his last go around, and at this point in his political career, the haters can truly F off. He also looked like a man, who unlike last go around, realizes this his moment. Just seemed really at peace with the situation. I felt he had a good rapport with the crowd as well, and that the audience seemed to anticipate his responses.
Also, he crushed the Bachman and drug question. They avoided feeding him any real economic policy questions, but no worries, those will come. Yes, he stumbled in the closing remarks, but only because he was eager to talk about issues, not pump his website or pander for donations. Definitely seemed the most authentic out of anybody on the stage, and you could tell he had "been there, done that".