And it is just damn awesome! And absolutely worth seeing it in 3D (or IMAX if possible). It's definitely a summer movie with a lot of action and too little time spent on developing the characters, but even so it's fun, likeable and BIG. Spoilers below.
The movie dives straight out into the action, with some absolutely gorgeous shots of the main mecha, Gypsy Danger (which could rightly be called mecha porn), and it pretty much never stops from there. The kaiju however are never quite that clearly shown on screen, and all of the battle scenes take place at night. The fight scenes do get a bit confusing and shaky at times, but those are only rather brief moments. You can actually tell who's punching who most of the time.
The characters are likeable, but they are little more than a bunch of tropes stringed together. They are stringed together rather well (with props to the actors who had to carry that), but there's just not a lot of time spent on developing them. The stand out characters for me at least were the two scientists studying the kaiju, who manage to both be the comic relief as well as the characters that do the most growing and stepping up to the challenge.
The movie does have some moments of "If you say it fast enough maybe people won't notice it it makes no sense at all!" The one that jumped out at me the most was the damn wall of Life which seemed like an incredibly stupid idea. So you build a wall to keep kaiju out and then decommission the robots killing them, so the plan was what: letting them roam free around the Pacific? Wait until they made their way around it? Not to mention there's no wall that would actually stand up to more than a couple of punches from a kaiju! The second that stood out in a bad way was when they were trying to explain that either a) the kaiju were the original dinosaurs or b) that the aliens tried to invade when the dinosaurs were roaming and failed because the planet was too un-polluted. Or something. It's not quite clear. Otherwise the movie avoids several other dumb moments by just not saying anything ( like what powers the other mechas - if not nuclear, then what?), which is probably for the best.
I would have liked a little more exploration of the characters and the pilot teams and what that neral link meant for them. you can't just have someone else's memories in your brain and still be the same person you were before. There's also an inexplicable lack of female characters, and I think only two have speaking roles (one of which is about 3 lines). Even all of the world leaders shown are male (and mostly white, at that)!
All in all, everyone I went with really enjoyed the movie, and if you pick one movie to see in 3D this year, this should be it. Now excuse me, I need to go find some more awesome mecha posters.