In short, Public Enemies is very, very, VERY gay. I don't mean "gay" in the perjorative sense, mind you. Though I, on occasion, use "gay" as a negative term (mainly because I went to a public high school), in general I think it's in poor taste. The gay and lesbian community in this great nation of ours helps to maintain our cultural diversity, and their contributions cannot be overstated.
When I say that Public Enemies is gay, I mean that the theme of the film appears to be about how much Superman and Batman desperately want to have sex with each other. Now, the original comic had some homoerotic subtext, as has been commented on by very scholarly works, but the animated feature cranks it up to eleven. Public Enemies is like the Elton John Birthday Party of animated features. There's Batman's sudden shift in attitude whenever Lois gets mentioned, for instance. Or, the thrilling conclusion, where the two protagonists shoot each other a look that suggests that Superman is about to crash land his rocket into the Batcave, if you catch me drift.
Now, overall, Timm and company are generally faithful to the original story, though it's trimmed down a bit for time. There are two major changes to the plot, however. First, they changed why Superman is branded an outlaw by Lex. In the comics, it goes a little something like this...
LEX: You know kryptonite, that rock that's basically poison to Superman? There's a HUGE chunk of it coming to Earth that will kill us all; Superman is clearly behind it- ARREST HIM!
Granted, the populace of the DC Universe has never been known for being overly intelligent, but I find this a bit much. In the film, they change it to Superman being framed for murder, and do so in a fairly clever fashion.
The other major change regards Captain Atom. In the comic, he's arguably the most important character after Supers, Bats, and Lex; he ultimately saves the day. However, that would fail to impress upon the viewer how awesome the power of Superman and Batman's bromance truly is, so Cap is pretty much relegated to background duty.
They kept most of the choice bits of Jeph Loeb's dialogue, and there are some great action scenes, but for the most part, this film feels like it's missing something. Maybe it's the run time; it's only about 10 minutes shorter than the average for the rest of the DC features, but it feels really rushed. Or maybe it's because a lot of the big moments have been done better before. President Lex vs. the Superheroes was better on Justice League Unlimited, and Superman saving Batman after Batman saves the world was done better in the Justice League episode Starcrossed.
Honestly, I didn't love this. It's not bad, but I wouldn't recommend buying it. It's good for a rental, but that's about it.