Rotten Tomatoes ran a feature on Terra a few weeks back, here’s the released clips. The bottom link is to the first video, and the rest can be accessed through the playlist to the right (or you can just watch the vid to the end and wait to load you to the next one).
‘Captive’ is by far my fave cos’ it shows our Wall-E lookalike, Giddy fighting with this directives, much like our trash-bot.
‘The Race’ is one of the most beautiful scenes from the clips, and it reminds of the Pines of Rome segment from Fantasia 2000 because of the giant flying whales. 
‘Ceremony of Life’ is the more poignant clip, with Lt Stanton questioning his role as a soldier of war.
‘Station Under Fire’ and ‘Floater’ are heartbreaking because of their themes of sacrifice. I can’t wait to see what happens after the end of the clips, and whether the characters made it out alive!
Have a look at them, and see if they change your mind if you’re still a skeptic. 
Yeah, I saw those Rotten Tomatoes clips on TV. Some of the bad stuff they were saying about was kinda’ funny but the film deserved alot more than it got including critical reception. 
Just watched and enjoyed this film. Very impressive effort given the limitations of shoestring budget and a small animation team. Actually, it looks like it cost a lot more money and time to produce than it reportedly did. It “stumbles” in its story, probably due to (again) budget limitations. It’s highly likely that the filmmakers had a lot of fine ideas that had to be super-compressed to keep the running time down. In the middle section, plot points get glossed over and it’s on to the next one like falling dominoes, with only the sparest exposition necessary to maintain coherence. In some respects, that works out well. Various sci-fi TV series could have built an entire season out of some of the ideas that get a few seconds of screen time in Battle for Terra. But more often it leaves one vaguely unsatisfied by unanswered questions.
To answer some points aired earlier in this thread, neither the humans nor the Terrans are portrayed as uniform, one-dimensional species. Yes, the humans are the aggressors, but not all of them agree to the military approach–and that applies to more than just the central human character who embodies the “change of heart” concept. Also, the Terrans are more than peaceful floaters content to graze in lush comfort. Different temperaments emerge and cause conflict among the individuals of each species. If anything, the message on military aggression is about exploring options before making a move. Fools rush in, an always-relevant message that Sun Tzu and Clausewitz, two great military theorists in human history, expounded upon in various ways.
Bottom line: Much better than its budget and box-office performance suggest, worth a look by the tolerant sci-fi/animation fan.