I read this while reading an accompanying book about Austen's works called Bitch in a Bonnet. The accompanying book was not great but I felt the title befitted Lady Susan pretty well.
I concur with BT -- don't rush to read it. It's basically the author's blog posts on Austen compiled into a book pretty much unedited. Plenty of sarcasm and snarky comment, but essentially not much more than an edited summary of the books' contents. It may have worked well as a blog, but for book-length (especially *that* length) it's really rather thin.
Ah well, at least it was a Christmas gift and not something I spent money on. :D Thanks for the heads up; I'll probably just dip in and out of it occasionally at some point, rather than rushing to read it.