Answer:
Nice question! I've read through and loved both franchises, but if I had to pick one, I'd definitely go with the Percy Jackson series. As a whole, every single character is fresh and brings personality to the story. The way Rick Riordan switches between POVs in the later serieses is amazing and never stops being investing. The characters are full of energy, and you don't even realize you're in deep until you can't put down the book. The whole universe is one to get lost in.
Not to mention the incredible diversity that paints each character and makes them all special (as cliché as that sounds, bear with me!). Different upbringings, nationalities, ethnicities, sexual orientations, gender identities, Riordan makes it so kids can see themselves in the heroes he writes.
I've read a comment recently that went "'Percy Jackson' is incredible in that, Percy isn't a hero who overcomes his ADHD and dyslexia, he's a hero <em>with</em> ADHD and dyslexia." The things that make the characters different make them strong, unique, and fun, not something that hinders them.
My favorite characters are Leo Valdez and Nico di Angelo!
