Quite a bit of fun. My first Terry Pratchett novel and I appreciated his writing style. It reminded me vaguely of Hitchiker's Guide though not so thick on the humor. I really liked the lead character, the supporting characters, the dialog, and just generally the world. The concept of divides between races is ever prevalent even beyond the dwarf vs troll aggression, like vampires and werewolves.
That's really what I enjoyed the most: the world and the city of Ankh-Morpork. The plot -a standard murder mystery (if "standard" includes trolls and dwarves)- did actually keep me interested throughout as the tensions between the dwarves and trolls rose. And while I wasn't exactly satisfied with the ending, it wasn't terrible by any means and doesn't spoil the rest of the book.
Me being new to the Watch and Discworld period might have actually helped me enjoy it more, I'll admit, but I'd still say that's a positive: I came in completely fresh and didn't feel lost at all. It's a fantasy story that I enjoyed very much and I'm definitely going to read more Discworld.