I've not read the books, and I enjoyed the series. I won't say it was all utter delight, but it was very good. Far, far better than the films (which probably has something to do with my like for it).
If they took it too easy on what a douche Poseidon was in myth, I get they had to avoid making Percy's dad hate worthy, and they pulled no punches with rest of the lot. I enjoyed how much more complex all the focal characters were. Luke, Grover and Annabelle being standouts.
I extra loved how strong Percy's mom was. Like Lois Lane or Steve Trevor when written well, you can see how she's as much the source of Percy's strength as his divine genetics.
I look forward to more.