Vague spoilers for all Percy Jackson/Heroes of Olympus/Trials of Apollo that I've read so far.
tl;dr: the books are long but nothing is happening in them (or maybe I'm just not interested in the action? That's very possible).
It took me so long to read this book. As I was reading I thought, "Wow, I really miss Percy Jackson." And I always get a little frustrated with Percy Jackson when I read his books (I always end up thinking, "Let Annabeth narrate for one second, please, Percy.").
I also thought, "I kind of miss the format where they only have a week to do every single thing in every single book." And then the monkey's paw curled on me because I don't know if I want to read the next one. I still have very mixed feelings about the Roman demigod kids. Like, I like Frank and Hazel individually but their relationship skeeves me out. And I like the concept of Piper but she wasn't well-written in HoO (her description was even offensive with the eagle feather and everything if I'm remembering correctly?).
I'd prefer it if the books were shorter and more action packed... like Percy Jackson. Maybe I should just reread those. Or finally finish the Kane series.