I thought the movie was very well done. The 3D effect was good. Didn't bother me, but my son had a slight headache afterwards. The one suggestion I would make is that they have more depth of field in some of the shots, since it's a little disconcerting when viewing 3D that things you're verged/focused on may be out of focus if they're not what the camera was focused on. I would caution parents to see it first before deciding whether they want their kids to see a movie where you end up rooting for the aliens against the humans. May not be the messages they want impressionable kids to get. The movie overall was very engaging.
This movie had everything you could want from a movie (except maybe comedy). The acting across the board was outstanding. The story was engrossing. The content thought provoking. The ending, one of the few I didn't see coming.
DON'T expect scientific accuracy or even reasonableness. Don't expect plausibility. However, despite those aspects being annoying at times, it was a fun movie to watch. Fine for children (rare these days).