Just got home from seeing it, still decompressing so I won't try to give any detailed impressions yet. As a life-long fan of Godzilla (32 years old, and I'm gonna have to make the distinction here that I was a fan well before the '98 film), I walked out impressed and happy. I know there were several points where I was quite aware I was smiling like a moron seeing Godzilla on the big screen, doing his thing properly.
Initial impression though is, very good. My wife (who's never seen a Godzilla movie before, not even 98) thought it was great and is presently looking for a movie poster for our office. We're trying to coax the in-laws out to see it so we have an excuse to watch it again. It's worth noting we don't usually go out to movies (the last one before this was The Dark Knight, before that was Avatar), so going to see it again is a bigger deal than it sounds like. My wife mentioned she's even willing to buy their tickets for them (and thee are IMAX tickets, so ~$20 a head).
Worth noting that I saw it in IMAX 3D (the first 3-D movie I've seen since Captain EO at Epcot back in 1989) and I went in expecting to be annoyed by it and worried I'd have a headache. Happy to report the 3D is unobtrusive and wasn't much if a distraction after you get used to it (my wife and I settled on 'about 5 minutes' for that to happen). It doesn't really contribute that much to the movie but doesn't detract either. And it was worth it for the IMAX screen and sound (there were no non 3-D showings at this theater).
I know a sequel is coming. I'm more than okay with this.
Edit: Ah, some Pacific Rim discussion. I caught it on HBO since folks were talking about it in the thread before I went on media blackout. Was not impressed, it felt like Big Transformers That Don't Transform Beating Up Lots of Generic Monsters That Just Skirt Copyright Infringement: The Movie . Lots of CGI shit slamming into other CGI shit for 2 hours with a lot of poorly-written 'human' stuff wedged in. Godzilla, in contrast, felt like you got just enough monster (a lot of it tucked nicely into the background to give it a sense of scale, something Pacific Rim didn't really have because everything was CGI) with the human element serving to motivate the story and give you something to invest into other than "Will Godzilla win now or later". I also think Pacific Rim was a little too jokey (nowhere near as bad as Godzilla 98) whereas Godzilla didn't have a moment of levity that I can recall. Way too much "Look how badass it is to smash things with giant robots, with giant swords and he just hit that monster with a BOAT and junk, fuck yeah!", but that's what it was going for so I guess it worked. Just not what I want out of these kind of movies, I guess.