Milton's Paradise Lost is a masterpiece, but that does not mean it is easily read or that it is appealing to modern tastes.
The level of English in this poem is absolutely insane, and Milton floods the pages with his learnedness and his poetic writerly powers, which are near unbelievable. I don't think there's any question that there's some self-indulgence here - this work goes on too long by modern standards and some passages are difficult to enjoy. Sometimes you're just ready for Milton to be done with this and get on to the next thing. And Eve gets the lion's share of the blame for the ultimate failure of course; there's a level of condescension towards women there that will get your feminist side uppity and irritated.
But reading Satan's rebellious speeches and the incredible imaginative power of Milton's description of the war in heaven between the rebel angels and the good . . . there's passages here that have yet to fade and probably never will. When you consider that Milton was eyeing other great epics from the distant past while he was doing this, its no wonder he pulled out all the stops and tried to find just where his limits were.
So read in small pieces, because the language is incredible and dense and difficult to absorb more than 200 to 300 lines at a time.