I have been on a huge Superman kick lately and I was really excited to watch All-Star Superman. I just finished reading Superman: Last Son, Superman/Batman: Supergirl, and War of the Doomsdays. However, my impressions of All*Star Superman was not the greatest. It was an okay film, 'meh' comes to mind, and honestly I have not read the graphic novel so maybe my opinions are automatically jaded, but the story and the plot elements just did not seem to mesh properly. Lex Luthor's change of heart at the end of the film and the causality of Superman's demise seemed far fetched even for a comic book. Villains seemed to pop up out of nowhere and the conclusion was ambiguous at best. The animation was slick and the voice acting was well-done, but it does not make my top five. I will probably be giving the graphic a whirl soon, so maybe my opinion will change then.
As far as the Ultimate Avengers goes I was pleasantly surprised by the quality. Although its predecessor was better Ultimate Avengers 2 is still solid and ranks above All*Star Superman by a good bit. Having Captain America, Iron Man, Thor, Giant-Man, Wasp, Black Widow, and Nick Fury with the addition of Black Panther is phenomenal. I love the group's dynamic, and with Iron Man and Thor being amongst my favorite superheroes it is cool to see them in action. I would recommend this film as well as the first. They are great animated flicks based on a great line of comics by Marvel.
If your a comic book fan I would highly recommend checking DC and Marvel's animated catalogue. Some of my favorites include: Batman: Under the Hood, Ultimate Avengers, Iron Man, Superman/Batman: Apocalypse, and Superman/Batman: Public Enemies.