I did see Ultimate Avengers and I liked it, although jaydawg can't understand why. The difference is straightfoward to me; my expectations are lower for Marvel animated projects, especially after a drought of some 2 years since EVOLUTION ended, and I have a pro-Marvel bias. I see it as something like X-MEN was in 2000; not a great movie in itself, but as the set-up chapter to introduce a team, a universe, and have some action, its not bad.
DC-related toons, on the other hand, have been setting THE standard for animation for the past 12 years, so they always have high bars to climb. That said, the trailer to BRAINIAC ATTACKS wasn't thrilling me, and the reviews aren't promising. But I'll still rent it, even if its not canonical. Obviously the WB wanted to crank out ANY new Superman animated material now that SUPERMAN RETURNS is hitting threatres in June, and obviously the rush job treatment is what they got. But I'll judge fully next month, or whenever I rent it.