"Heyer's fiction is intended as an accurate psychological depiction of human beings in exactly the same way that Winnie the Pooh is intended as an accurate depiction of ursine behavior. Her characters are one-dimensional, charming, funny, and, once you've read enough of the books, impossible to distinguish from one another."
This is the best sum-up of Heyer I've seen yet! I find myself both charmed and annoyed by her work, and have to read it in small doses otherwise I get tetchy.