I guess if you're a long term reader of Superman you'll wonder how they manage to condense the events of the hige Doomsday arc into a 75 minute film. Well, they drop a lot but let me, without spoiling too much say that they keep the best aspects. They drop the "Four Supermen" replacements idea completely but that's understandable, there's just not enough time here to tell the extended story.
What story there is is tight, and it's self contained enough that someone with only a basic understanding of Superman will be OK to watch this without worrying about getting lost. The voice cast is strong and the animation is as you'd expect from Bruce Timm's DCAU very Fleischer and very iconic.
I think this, at the current price of only three pounds, is a bargain and a half - snap it up and enjoy one of the better animated Superhero titles.
Oh, there are great bonus features too including a full length commentary and interviews with the cast and crew.