Hmm. Personally, I think it is the Kane Chronicles trilogy by Rick Riordan. Maybe because readers are comparing it with Percy Jackson and some of the PJO fans are nervous that it might outshine PJO.
For me, I would recommend people to read KC. It is a fun read. It gives another perspective of Gods that they are not to be worshiped, but to be allies or more likely be friends. Sadie and Carter also depict the main characters of PJO: Percy and Annabeth, showing that the pair shows similar attributes, but once again this should not kept readers from trying to get into the books.
The plot of the trilogy is really exciting. I see the depth of how limited the Gods are and even they need to be pushed beyond their limits, even if who benefits is only a mortal.