Lots of glitzy special effects, over-the-top battles (and duels -- like, one at a time is never enough, you have to have at least two going, or if not you have to have multiple lightsabres involved), pretty costumes, and Hayden Christensen still can't act to save his life or anyone else's. In fact, he seems to have infected Natalie Portman as well. There were a couple of moments where one or the other of them had expressions on their faces that almost seemed like they were real human beings, but it never lasted. And Natalie's little-girl voice in particular nearly drove me around the bend.
My husband liked the way this movie tied everything together and explained everything rather neatly, which I agree it did, but not in any way that was clever or unexpected enough to grab me. It was a bit like playing connect-the-dots, which may be exciting when you're small and still learning your numbers and can't tell at a glance what the final picture's going to look like, but since the audience already knows the final picture (or at least, anyone who's seen the first trilogy does), the progress from number to number just isn't All That for most viewers. Unless, of course, you're simply besotted with the whole universe Lucas has created and fascinated with the worldbuilding for the worldbuilding's sake, but for me anyway, that just isn't enough.
What these movies really needed, I think, besides a little less attention given to special effects and a little more to things like credible acting and dialogue, was a Han Solo-type to skewer the self-importance of all the other characters. Luke Skywalker would have been a boring whiny farmboy (okay, he sort of was a boring whiny farmboy, but still) if not for Han taking the mickey out of him all the time. And, of course, all the Han-Leia banter, where most of the best lines in the original trilogy originated. If the younger Obi-Wan had displayed more of the dry wit that Alec Guinness did (after all, he occasionally had his moments in the first two films, so it could have been done in this one), it might have helped. But I suppose Lucas was afraid of people accusing him of poaching from himself, so he dispensed with most of the wry humour and character dynamics that made the first trilogy (or at least, the first two films -- I'm still ambivalent about RotJ) enjoyable and substituted lots of sound and fury instead.
So ultimately I guess my reaction to the film, and indeed this whole prequel trilogy, can be summed up in one word: *shrug*.