The quality of the animation is fantastic. Just cinematically this film is beautiful with various camera angles and distances used for effect. Characterization is spot-on and they really used a wealth of characters, not just the "big three."
The thing that put over the top was the fight sequences. Simply fantastic. I struggle to think of better fight sequences in any superhero film - animated or live action. They had to have a fight choreographer plan everything out. The Wonder Woman mid-air battle is very dynamic. In group battles they brilliantly used characters fighting in the background to keep you informed on what each person is doing (after all, when, say, 15 costumes are fighting at the same time it gets a bit chaotic.). Characters improvise and use different moves based on individual fighting styles and powers. DC's attention to detail awes me.
In conclusion, it's a good time to be a fan of comic books with all of the high quality live action and animated television shows, theatrical releases, and direct-to-DVD releases that have been coming out. Justice League: Crisis on Two Earths is just one recent example that shows when Marvel and DC try to outdo one another, the winner is the fans.