I was worried we'd lose the characters a la the Matrix sequels, which, as you'll recall, went for joyless personless action sequences and straight into dullsville for two movies. And though there were action sequences to beat the band in POTC2, each one maintained the characters and dialogue and humor throughout each; there's your difference. Sure, it was aiming for a bit of over-the-top; sure, the storylines got convoluted enough to be confusing. But I felt like this film simply ramped up from where it left off, knowing the viewers knew Sparrow and Will and Elizabeth already and didn't need to see them established all over again, just--here's what's key--as long as they kept the characters doin' the stuff that made us love 'em. Which they did. Sparrow flounced, Will hero'ed, Elizabeth refused to be a damsel-in-distress. And they all stayed cool. Fun stuff.
I know I was the only one in my theatre who said, "It's Paolo from AbFab!" but surely I wasn't the only on my flist?
(Everyone has my permission to get spoilery in the comments, so be advised.)