I loved pretty much everything about this story. It's a great introduction for Benny, the villain is imposing and the threat carries weight, the Doctor's motivations are fun and complicated, and Ace is well fleshed out as a young adult trying to find herself. The fights Ace and The Doctor have are cathartic and compelling, I always love to see cracks in their relationship caused by The Doctor's scheming and Ace's stubbornness, and the Doctor's clear manipulation was JAW DROPPING. I read passages to my friend and they half-jokingly told me The Doctor was "pulling a Lestat" when I got to the bit where he tells Ace how alone he'll be if she leaves, puppy eyes and all. Incredible stuff.

Now, as for my criticisms, I wasn't a huge fan of Jan. He seemed a bit bland, and, if his romance with Ace wasn't completely necessary for the story to work, I would probably just put him on a shelf with all the other male love interests writers want to constantly throw at Ace and forget he existed. But that's really the only big thing.