And that's about all that needs to be said.
The sum and whole of the movie is Giant Robots, extremely well-rendered in CGI. Even the monstrous kaiju aren't as interesting, or even as well-detailed (though they're pretty good).
Frankly, everything else is B-movie quality. The plot itself is recycled from any number of sports movies or heroic sacrifice war movies. The characters are mostly cardboard cutouts, with even the main 3 being quite two dimensional. The acting was reasonably good, however, particularly given the limited amount of characterization and opportunity that the script gave them to work with.
There's a whole bunch of cliches and stereotyping going on, and big enough plot holes to drive a truck through.
But that's not the point: the movie is just about watching Giant Robots fight Huge Monsters, and trash the scenery while doing it. If that's what you want, then it's glorious. If you actually want something other (like, maybe an actual story, rather than a 2-hour trailer) then you're in for a serious disappointment.
Personally, it fails as even a popcorn film, because, well, there's no film - it's a bunch of action scenes stitched together with dialogue scenes that you just don't care about, and can't wait to get back to the monster-trashing. It's about as good a movie as Battleship, for mostly the same reasons. But, the Jaegers sure were cool...