I'll pile in on what is already pretty well answered.
I loved the entire series. The first book feels different to the remaining 3 but I did not find the remaining 3 lacking. By no means are they perfect but in some way, that's better. As some other people have mentioned, there is some controversy surrounding the Endymion books but I found out after reading them which confirmed by suspicions after reading the books. Some politics definitely leaks in so you'll have to make up your own mind on whether or not you'd like to partake.
In an attempt to answer your question though, yes, the sequels are worth reading in my opinion. No book is yet to replicate the scope of the world that is created in Hyperion. I love the lore that creeps in and the individuality of the characters which is best showcased in book 1 but is definitely present in book 2. The overall story is incredibly well told and satisfying. The end of book 2 was great, I did not realise until reading comments that others did not enjoy it as much as I did. Books 3 and 4 tell a different, yet related story, which is also genuinely wonderful. I was swept away in to the Hyperion universe by all of them.
If you do decide to read them, I hope you enjoy.
As a side note, the audiobooks are great but the narrator is not consistent with certain names and locations which is, to this day, one of my biggest pet peeves about audiobooks (albeit generally)