SF series are, if well written, often tense, fast-moving, page-turners with action on an epic scale. What they are rarely is emotional and touching, leaving the reader moved by the dignity, suffering and, ultimately, tragedy (in its classic sense of inevitability) of the characters.
The Rise Of Endymion is both of these but it is the emotional grip it takes on you that is most unusual. At one point the impact of one of the revelations on me was so strong that I felt as if I had been slapped, and had to put the book down for a while to recover.
The final 'twist' is signposted so much that I guessed it about 300 pages in advance but the cleverness of the writing is such that this in no way diminshes the power the text has over you. Like the previous reviewer my first inclination on finishing it is to go back to the beginning of the Hyperion Cantos and read it all over again, but more slowly.
This is the best series I have ever read, far better than Dune, Foundation or any of the usual suspects always trotted out as comparisons when a book like this is published. Read it and enjoy - but don't think that you can remain unaffected by it!