Pacific Rim is one of the greatest, dumbest action movies I've seen in a long, long time. And I mean that in the best possible way. This movie isn't dumb like, say, Star Trek Into Darkness, whose villain's behaviour can only be reconciled by assuming he is both working for and against another villain simultaneously, or The Dark Knight Rises, which completely wastes the entire emotional arc of the trilogy by having the people of Gotham not do a damn thing to save themselves. No, Pacific Rim is dumb in the biggest, coolest, most fantastic way possible, in the kind of way that doesn't let silly little things like reality and physics get in the way of grandiose displays of pure spectacle.
For example, there's a scene in the trailers where the hero's robot, Gipsy Danger, wields a cargo ship like a sword. This scene is dumb as a box of hammers. Just picking up a ship like that from one end would probably snap it in half amidships, nevermind dragging one end along a pretty long causeway. And then it gets swung through the air and collides with a giant monster. Multiple times! You can punch a hole in the hull of a ship like this by hitting it with a particularly sharp rock; the chances that it would've remained intact long enough to serve as a make-shift weapon for not just one, but several strokes, is essentially nil.
But it looks cool as hell!