I never read the graphic novel, I think I would have enjoyed it more. I really, strongly disliked this movie. I thought the voice for Batman was horrible, as well as the voice for J'onn. The two voices might have better if they were reversed. The other voices were all good though. I simply didn't like though, I thought it was boring, it dragged on... or as a paradox to that it felt rushed, as if they were just trying to cram in all these stories at once, and trying so hard to make each one of them meaningful. I don't know. I immensely hated Superman Doomsday as well. It was nothing like the old comic story. Maybe the problem with both was that fact they were limited to 70 or 75 mins. Maybe if they had been longer... that's just not enough time to tell these stories properly.
On a side note, I know Bruce Timm did the DCAU and related shows for 14 years... but the continuity he established was incredible. I understand that he was bored and wanted to try his hand at some different projects, but I'd say he's ultimately failing. It's time to get back to the DCAU. Make DTVs from that continuity. I want new JLU. Also i didn't by the New Frontier, because after Doomsday I didn't know if i'd like it (and thank god i didn't waste the $$$) However if it was part of the DCAU then simply for the sake of being an obcessive collector I would have purchased it as well as Doomsday and Brainiac Attacks... why, becuz i'm sucker, and I have the box sets & movies of all the DCAU. Seriously though they're loosing money and I'm sure i'm not the only sucker who would have did this.