i thought 28 days later was way better tbh, not that "weeks" was a bad movie because let's face it, it's pretty hard to make a bad movie when there's zombies involved...but i dunno, the comparison i would make is:
-with 28 days later they took a regular guy and threw him into a totally implausible situation, and walked away with a fantastic and truly scary movie. you identify way more with the protagonist than in the sequel, and it makes for way more suspense.
-with 28 weeks later they took an already implausible (though awesome) scenario and added an extra layer of implausability--the way the whole occupation thing was played out seemed really contrived to me. then they threw in some less-believable characters and a bunch of big-budget action sequences. i could have cared less about the kids getting torn apart so it was just less suspenseful and scary, although the first scene (without them) is pretty exhilarating. the whole thing seemed kind of confused and less genuinely scary than the first one, and relied a little too heavily on cheap-shot surprise moments to drive the horror.
that said, it was worth seeing, at least as worth your $10 as any other movie
...if you liked the first one you'll find this one quite enjoyable, if somewhat lacking in some respects. a couple of my friends who like the first one said they thought it sucked; i wouldn't be so harsh but i dunno about the rave reviews i've seen for it. i just love zombies, really.
still can't believe i paid $10 to see a movie and it wasn't because i was trying to get into a girl's pants.
also watched argento's PHENOMENA recently, which was phenomenal. that little fucker was creepy as shit! also i've never seen so many maggots and/or rotting body parts in one movie, cheers to that. unfortunately my gf fell asleep so i didn't get into any pants there either