I agree with Cassandra. I don't think it has a different vibe, and I think the 'vibe' right afterwards was different here than in a lot of the country that wasn't here.
People went to help, but that's what people do, I think all over, and certainly here, in a crisis. For lack of a better term, and I'm not sure how to put it so it won't possibly offend anyone, I think NYC is less sentimental over 9-11 than many other places. I mean obviously people are, and tons of people knew someone or many someones who were killed, but ... I dunno; I feel people other places view it very differently than people here, and not just in an 'experienced it' way.
It's like how shocked people were. Again, obviously, people here were shocked; it was here, it was real, and it looked like a damn movie. However, no one I know in NYC was shocked at the basic fact that terrorism happened here. The specific was shocking, but not so much the general. Like the old video for some Van Halen song that had all these 'facts' scrolling across the screen - one was something close to 'there's a madman loose on the streets of your town.' I remember seeing that a long time ago and laughing because, well, no shit.
I'm not being particularly articulate here, but it's sort of, from my perspective, that people elsewhere (I'm generalizing, of course, not speaking about every person each place), seem to feel a loss of innocence about 9-11, a turning point that the U.S. was attacked, the first real, 'the big, bad, they could actually get us,' thing, that people in NYC were mostly well aware of and inured to. Not that anything that big had happened, but it wasn't some loss of innocence that it did. New York was and is a target. Has been for more than the lifetimes of anyone here, and everyone here knew it September 10, 2001, and knows it now.