It's final novel from Hyperion Cantos.
For me it was really good. Especially the ending. I may be biased but I really like all books that have at least a bit of time travels and conflicts issues related to that. In "The Rise of Endymion" there is not much of that but there is something. As in all preceding novels it has a lot of philosophy and poetry. It may sound daunting. I'm not really fun on poetry but in base of "Hyperion Cantos" it really fits the story and style of writing.
I would say it's hard sci-fi. You can read more about empathy, origin of artificial intelligence and so much more.
If you liked previous books then just go read it. If now start with Hyperion.