Really entertaining. It has most of the voices from Justice League Unlimited, and if you watched JLU, there are alot of recognizable faces. It's extremely action packed, though I will admit it borders on cheesey at times(Japanese Batman/Superman robot, lol?)
Only downside is that it's a little short.
And Amanda Waller seems to get fatter every time somebody animates her. I liked JLU's style for her a bit more then this movie's.