This will be short.
All I will say is:
WHY ARE THERE ONLY THREE BOOKS IN THIS SERIES?!
Talk about unfair. This series has just as much action and humor and adventure and mythology as the other two mythological series of the author.
Yes, I am biased.
You know what I wish? I wish Riordan would write a series where ALL three sets of characters would work together. THAT would be insanely cool.