As a bit of a fan of anime, giant battle suits are not a new concept. Evangelion, Voltron, and Robotech come most readily to mind. Outside of anime, Power Rangers have also popularized the idea, Transformers has something like it, and Godzilla movies have the robot MechaGodzilla.
In many ways, Pacific Rim is a step forward in the quite enjoyable kaiju genre. While the story may not be as rich (or as convoluted and messed up) as Evangeliion, the action itself is very nice. The kaiju are convincing, at least once you accept that such monsters could even exist at all. The battles between the kaiju and the mechs, called jaegers, are very well done.
Like I said, the story itself is rather on the simple side, and the movie follows a pretty standard formula. You can find elements from Star Wars, Independence Day, the anime series Evangelion, and of course Godzilla--I'm pretty sure that at one point I head the Godzilla roar, and there were snatches of music that reminded me of the Godzilla theme.
To put it simply, I pretty thoroughly enjoyed this movie! There is little objectionable in the movie, a bit of language but that's about it. I suspect this is the kind of movie we've been wanting from previous movies like the Godzilla takes Manhattan one, as well as Cloverfield. Forget little raptor-like Godzilla babies, forget jerky camera work that nevers lets one see the monster, give us giant monsters and robots slugging it out with each other, and lots of it!
On that front, Pacific Rim delivers, making it a very enjoyable, satisfying movie.