General points: Neither candidate was actively embarrassing. I didn't like either of them. I conked out almost immediately after the debate, rather earlier and suddenly tireder than I would have expected--I think I'm allergic to politicians.
The format wasn't as awful as I feared--the moderator handed them some fairly tough questions. Yay, moderator!
They were both fairly repetitious, though Bush was more so. and Kerry had more substantiating details.
Bush said one thing that struck me as reasonable--"If you say the war was a mistake, how are you going to gather allies to help you fight it?" (Approximate quote.) I wish Kerry would get more specific about changes in US policy instead of just saying that we need allies to do whatever we're doing.
Imho, the dumbest thing Bush said was "It is hard work. It is hard work to go from a tyranny to a democracy. It's hard work to go from a place where people get their hands cut off, or executed, to a place where people are free." Is it possible he doesn't know that the US has capital punishment and he's been supporting it? That "hard work" thing--he used the phrase a bunch of times, and it may be one of the reasons people have been calling him petulant: "How can you criticize what I'm doing when I'm trying so hard?"
Bush had some odd pauses toward the beginning of the debate. It sounded to me as though he just wasn't interested, though I've since seen a theory that he had an ear bud.