Sounds like: Paul Simon, Graceland meets The Beach Boys' "Oooo"s meets Arcade Fire when they sound a little like the Beach Boys meets The Royal Tenenbaums meets what you think Cape Cod should be like but really isn't meets Columbia Univ. prep.
Singer: Ezra Koenig, who's like 23, is actually awesome live and really added enthusiasm and some screaming to the songs (I love screaming), and basically, he's adorable. You can probably remove/replace the rest of the band (sorry, guys), but this kid is pretty solid. Even if you think the music is juvenile and lame, he comes off as pretty talented and comfortable on stage, often chatting with the audience (I like that too).
Crowd: UM whiteys, young blond chicks, really young blond girls, old balding dudes, and NO ONE I knew. My friend said she knew a buttload of people there, but they're a little younger and went to private schools. Not my scene.
Show: Very enthusiastic audience, one of the best I've seen in Miami. However, consider that at most shows people just chug their drinks and leer at one another. Even at Radiohead, no one in our area but two creepy teens in front of us had the balls to dance, and that wasn't even in Miami. Most people at this show were bouncing around having a lot fun and the lead singer even said that this was one of the best crowds they've ever had. Represent.
Sound: I haven't been to Jackie Gleason in years, maybe even since I saw David Sedaris speak there, but the sound is fabu! It makes me ashamed of all the other places we listen to live music at, except Churchill's since you can always interact with whomever is on stage, if you really wanted to. So, cheers to the Filmore, worth the extra few bucks.