Very good movie - great to see Vin return to the series. There are excellent car driving/racing/chasing scenes, good interaction (though Michelle Rodriguez's role was minimal) between the characters. The plot acknowledged the gap between the movies without dwelling on it or expecting viewers to have seen the first movie to appreciate this one.
I did not see this movie in 3D, but there were only a few places in the film where I felt I was "missing something" by only seeing it in 2D. The characters were well-voiced and the animation/effects looked great. Given the promos for the film, the first "real" scene almost made me think I was watching a different movie. But, things quickly fell into place. There was humor aimed at the parents (e.g., Close Encounters reference, Saturday Night Fever-themed costumes), but the action was a hit with the younger moviegoers. The plot is thin, but acceptable given the target audience. And, the "be yourself" message is one that can benefit all ages. The ending leaves open the possibility of a sequel, so you never know when these monsters may return!