I liked it a lot. Hyperion was essentially devoted to tell the (back)stories of the characters. Fall of Hyperion is the story of what happens on Hyperion (and doesn't stay on Hyperion). War is imminent. Outside of Hyperion, we see how this is managed by the Hegemony government. On Hyperion, the pilgrims have arrived to the Time Tombs and await the confrontation with the Shrike.
This was a very absorbing read. While Hyperion was more interested in the story of the characters, Fall of Hyperion gives a fair amount of universe development. Did I say already that I liked it a lot? I did. I also now have two versions of it. I have a (French edition) paper version that, for some reason, misses 40 pages approximately at 1/3 of the book. When realizing that, I got up from my bed (and cosy duvet), and re-bought it as Kindle version to read on my phone and not interrupt my reading. I'm not sure I would have done that for just any book.