I went and saw the movie yesterday and it was pretty awesome. If you have any love for Godzilla or giant robot anime (like Mazinger) from the 70s-90s you'll feel right at home. Of course the giant robot stuff is all great, but what Pacific Rim does right is it keeps the story and human drama simple and straightforward as to not muck up the good stuff. I imagine this is what a lot of folks might have wanted out of something like the new Transformers. Rather than coming up with some convoluted story with worthless plot twists or origin stories you more or less have a straightforward struggle for survival against mean monsters. This isn't the first time I've said this in the past couple of years, but it's become a refreshing when any sort of movie or game is willing to keep things simple. The conflicts that erupt between people are believable even though they play out in a somewhat cartoonish fashion. The characters themselves are all fairly generic archetypes for this sort of thing, but they're all played well. In the end, you just have a movie that's just enjoyable that isn't weight down by shit that makes you hate the movie (like nearly everything in Transformers).
My only complaint was there wasn't enough of the Russian team. Having the Soviet era style choir going whenever they were doing their thing was brilliant.
Edit: Oh yeah. Because of timing I ended up at at 3D showing and I sort of think it was for the better. 3D seems like it has actually come some ways since Avatar and it felt like the usual clarity or color that was the tradeoff for the the 3D wasn't an issue here. Given the sort of big dumb nature of the movie it really worked well.