I started reading Paradise Lost, along with C. S. Lewis's excellent Preface to Paradise Lost, a couple months ago, but it ended up sitting on the shelf for a while and I only got around to finishing it now. I had written a bunch of notes for it, but I have since lost them - which is unfortunate because Paradise Lost is one of my favourite books - so my thoughts will have to be based off of memory.
Paradise Lost has some of the most beautiful writing I've ever read. Milton creates such vivid mental landscapes of Heaven, Hell, Chaos, and Eden that it really is breath-taking. I'm no expert on poetry so even if I can't explain how, Milton's writing has a big effect on me. I'm hooked right from the beginning, with Satan and his fellow demons discussing their plans now that they have been decisively beaten and ousted from Heaven. It's the cerebral, bookish equivalent of a great opening action scene in a summer blockbuster.
The way Milton writes Satan is very fascinating and he's easily one of my favourite villains of all time. I think one of the reason why Satan is so much more interesting than the good characters is that all of his motivations and arguments seem a lot more innovative on Milton's part, while the good characters tend to rely on traditional theology. But that's the way it has to be. It was probably inevitable that Satan would be the most interesting characters. That said I think that Satan is undoubtedly the villain, the also the main character, of the story. I agree with Lewis when he says that taking Milton's anti-monarchy political views and using them as an argument that makes the rebellious Satan a hero is a misunderstanding. It seems clear from Milton's writing that he considered God his natural superior, but not Charles I.
When Adam asks the angel Raphael about the structure of the universe, Milton is vague about whether the sun revolves around the earth or vice versa - a sign that the Galileo controversy was relevant when Milton was writing.
*sigh* I have more to say about this book, I really do. If I ever rediscover my notes, or even re-read Paradise Lost before I'm finished the Great Books, I may do a Part 2.