Greg Cox is a regular poster here so we're all going to say his books are absolutely brilliant
But seriously they are good adaptations.
I've enjoyed all the DC novel adaptations, I loved them back in high school when I couldn't afford the comics. I think No Man's Land is the best but I also loved Death/Return of Superman back in the day.
I'm still waiting for one of the Superman New Krypton saga. That would make a good book, it's long, but it had a very definite beginning, middle, and end to the story.