the problem with most of that screamo shit is the drums. a lot of those bands use this follow the vocals, dramatic, expressive style of drums. i dont know how to describe it, it's like the opposite of a kraut motorik or a ramones beat.
a lot of crappy punk pop and indy rock bands use it too. its like a "beat" (use that term loosely) where you can visualize the drummer raising his arm way too high for dramatic snare hits into a roll, into some weird breakdown for the sing along, another roll etc. if the drummer is any good , like in the case of party of helicopters, the drummer is good enough to maintain a beat amongst all the nonsense going on without resorting to this sort of style (poly rhythms?).. which is probably what makes some of their stuff slightly tolerable. slightly.
we're getting close to worse than pop punk territory i'm afraid.
edit: added " screamo" to make sure it was clear i wasn't talking about screaching weasel, who are of course LEGENDARY