James Joyner considered the performance and found that:

Overall, it was largely uneventful, but the president acquitted himself well enough. He came across as thoughtful and considered. And, while he was almost certainly prepared for hours by staff members, he didn�t appear to be giving the memorized speeches that one is accustomed to from politicians on these programs. Bush actually seemed to pause and consider his answers.

Brad DeLong thought Russert could have done a better job with his followup questions

Tim Russert didn’t seem to me to do a very good job. He didn’t ask what seemed to me the natural follow-up questions…Here are three examples

Go read’m.
Now, Kevin Drum appears to disagree a bit with James:

It’s hardly surprising that I thought Bush’s performance on Meet the Press was weak (“labored and uninteresting….like he was addressing a class of sixth graders”),

and expresses some surprise at the responses from NRO:

…but the fine conservatives over at NRO are piling on in a fashion normally reserved for Jimmy Carter op-eds…For once, I find myself in full agreement with National Review….

(Kevin quotes a number of the responses he refers to.)
I’ve watched part of it and at this point find it unlikely I’ll invest the time to watch the last half hour unless it is to reconsider what James described as pausing to consider his answers. My reaction after a few of these pauses was that bush was faking them in order to pretend the answers were considered. My secondary thought was that he was pausing in order to assure himself that he was dredging up the correct practiced answer for the question.
And, as Dave Ehhrenstein notes, these are frightening words:

I’m a war president. I make decisions here in the Oval Office in foreign policy matters with war on my mind.