To help you out in this massive review round-up, I've lumped them into two categories: "Greek Mythology-ish" and "Dairy Queen-ish". Sounds like weird categories, but just trust me on this one.
Hogwarts Challenge Notes:
1. The Battle of the Labyrinth by Rick Riordan (Percy Jackson & the Olympians, Book 4)
Weakest book in the series. Bad descriptions of sword play battles. If I weren't invested in the series, I'd have given up. But I didn’t.
2. The Last Olympian by Rick Riordan (Percy Jackson & the Olympians, Book 5)
Best book in the series. Great use of minor gods; good battle descriptions. I actually thought somebody else was the spy. Glad I finished.
3. Troy High by Shanna Norris
Modern YA retelling of Illiad. “Cassandra” was a good narrator. “Agamemnon” and “Menelaus” had their personalities reversed. “Hector” was true to the original.
4. Troy by Adele Geras
YA retelling of Illiad from woman’s POV. Different perspective on tried and true story. Great read. (Good intro to Iliad for new-to-mythology readers.)
5. Ithaka by Adele Geras
YA retelling of Odyssey from Ithaka's waiting POV. Another good work by Geras. (Good intro to Odyssey for new-to-mythology readers.)
1. The Off Season by Catherine Gilbert Murdock (Book #2 in the Dairy Queen Trilogy)
I already knew (and sort of liked) the characters. Kind of repetitive (always saying, “Schwenks don’t make decisions”) with telling, rather than showing in her writing.
2. Front and Center by Catherine Gilbert Murdock (Book #3 in the Dairy Queen Trilogy)
Best conflict in the series. Wasn’t sure how D.J. would decide. Glad D.J. started to stand up for herself (especially to Brian). Good resolution of the trilogy.
Percy Jackson Books 4 & 5 - Both are Care of Magical Creatures (Lots of Magical Creatures in these books)
Troy and Ithaka - Both are Defense Against the Dark Arts (War)
Troy High - Muggle Studies (The war is too metaphorical, in my taste, to be "Defense...")
Dairy Queen Books 2 & 3 - Both are Muggle Studies books