I thought it was a mediocre slasher flick at first, but after seeing it three times I have increasing respect for it and can now see how someone would cite it as one of their favorites. For one thing, the environment of the story is original a film school at a university, the students thereof, and their competition for a coveted film award. This is the only movie I know of that takes place in such an environment. Then there's the scene where the bad actress, Sandra, is murdered on camera by the killer and the film students watching the video think it's just a student film and that Sandra's acting has improved immeasurably. It's a very creative idea/scene for a film. I don't know of any other slasher flick that did this up to this point.
My 150 (or so) favorite movies:
http://www.imdb.com/list/ls070122364/

I haven't actually seem the first one, I really like the characters and the story line of this one.
Gretchen: You're weird.
Donnie: Sorry.
Gretchen: No, that was a compliment.

It is really underrated. I've seen it multiple times as well.

Wow. It's not even my favorite Urban Legend movie.