On the plus side, I'm starting to enjoy the Powers thing of taking some known historical characters and events and weaving an outrageous story around the interstices. I used to own a book about writing called "Telling Lies for Fun and Profit," (good book btw), and I think the Tim Powers book about writing would be "Inventing Wacky Conspiracy Theories for Fun and Profit."
In this case, its a mock gothic set in the early 1800's on the premise that for 800 years many of the major European poets got their gift from being victims of an elder race of non human intelligences that are sort of vampires, sort of Melusine snakes, sort of incubus/succubus shape shifting rock monsters. The story centers on the efforts of Shelly, Byron, Keats, various of their associates and a guy named Michael Crawford teaming up to try win free of the creatures.
Lots of this is great fun. So that's the plus. The minus is that I felt like it went on entirely too long and eventually it just wore out its welcome with me. The first three times they were in a pitched battle with monsters trying to devour them, I was right in there rooting for them. By the seventh trip through the same territory I was a little tired of the landscape and starting to think about what might be for lunch.
Still, I think its well worth reading, and there are many reviewers for whom it clearly didn't wear thin. So if it sounds interesting I say check it out and see how your mileage varies.