New fans? Go read the books, please!
So, I've been familiar with PJO since TLT that I read when I was 10 or 12. And I read every book ever since. My verdict? The show and the movies are equally bad but the show fails at what the movies managed to do: be entertaining.
Half of the important narrative plot points are taken away, so it's not really the story of Percy Jackson.
Annabeth has maybe 25% of her personality, Percy has maybe 50%. Grover is changed into something he never was.
The Gods' portrayals are horrible, save Mr. D. If you like Hermes, you will not like this show.
Overall, objectively, there were so many changes done that this story no longer works. Not only that, but the show fails to include Percy's disability into the plot as its main aspect; which was a GIANT thing in the books (they were written for RR's ADHD&dyslexic child).
So, we get no ADHD/dyslexia rep, we get no personalities properly shown in characters on screen, we get no mystery and self-discovery (they sort of know everything before they're even on screen), we get no chemistry (Grover and Percy don't even act like friends), we get no correct role separation (Annabeth no longer acts like a know-all she is, Percy is the one explaining the Daughter of Athena myths), and we get no rep for abuse survivors (Sally) because Gabe's no longer abusive I guess.
The show is bad in so many more aspects, but most of all it's direction.
If you want to have fun, watch the movies. If you want to experience Percy Jackson, read the books (but not HoO). Good luck!