This series is amazing! It's very very difficult to pull off the kind of redemption arc Stroud writes here, but he does it, and he does it well. I was a little skeptical at the beginning that Stroud was going to be able to write himself out of the constraints he sets up in THE AMULET OF SAMARKAND, but PTOLEMY'S GATE manages it with ease. There are a few other fantasy series out there that could take notes on what it takes to make redemption convincing.
Other aspects I loved: the development in the relationships between our three main characters, the contrast between the different voices as we switch perspectives, the complicated worldbuilding, heart-wrenching character moments of struggle and growth, and the satisfying way the plot hints laid in the first two books are fulfilled here.
I listen to audiobooks while I exercise, and the ending of this book completely ruined my workout--it's hard to do planks while crying about climactic battles and their aftermath! Seriously, this book has great bones as well as lovely prose, A+, I wish this series had the fandom of Harry Potter because I would love to read a zillion longfic set in this world.