I liked it a lot too. Sure the story felt a bit rushed in parts, and there were a couple of plot points that perhaps didn't quite fit, but overall it made up for all that and had a solid ending which was a little different from what we normally see in Superman animations. And I think it brought back some of the sense of wonder that is missing from a lot of this stuff, especially where Superman is concerned.
Supes really seemed like Superman, with a sort of god-on-earth feel that actually justified Luthor's fear/respect, rather than just another superguy on a world swamped with superguys. He actually used his intelligence a bit. All too often these days Supes is just one more hero. There seem to be so many other characters on earth who can take it to him, either because he has so many easily exploitable weaknesses - kryptonite, magic, red sun energy, energy draining, telepathy, or simply because there just seem to be a lot of uber-powerful characters these days. On a world where earth can defeat New Krypton in a matter of minutes, would Lex really be obsessed with the danger of an alien Superman? Would two renegade Kryptonians really strike horror into the world's population? I think this used the Superman character more as he should be.
Good animation too. Overall, a pretty good effort.