I didn't like the voices, the animation style, the storyline, and the fact that Superman dies and is cloned by Lex.
Didn't care for Justice League: The New Frontier either.
The DC Animated movies that I like are:
Superman vs. The Elite
Justice League: Doom
Justice League: Crisis on Two Earths
Green Lantern: First Flight
Batman: Under the Red Hood
Superman/Batman: Public Enemies was decent.
"I do not feel obliged to believe that the same God who has endowed us with sense, reason, and intellect has intended us to forgo their use." - Galileo