Some of the negative reviews here seem to be because of the varying expectations of the reviewers: so I guess it's worth saying that this isn't an `introduction' to Jane Austen - this book relies completely on a fairly close acquaintance with the original. In fact it is Austen's original text, intersected and broadened by the interpenetration of the `horror'/SF/imperial adventure genre epitomised by authors like Rider Haggard, Conan Doyle (The Lost World rather than Sherlock Holmes), Jules Verne and later `B' movie spin-offs. And it's precisely the fact that this is written in Austen's measured, balanced formal prose that makes it so funny.
The text investigates the borders of genre in an insistently post-modern way, and finds them to be far more permeable than we might expect. It's not just the Austen romance, we find, that can be hijacked by early horror/SF, but that romance can completely hold its own: the shape of the genre may be bent and distorted but never eradicated completely. By mixing such seemingly-separate genres, this actually serves to draw attention to both their similarity and dissimilarity: refusing to play by genre rules serves not to make genre irrelevant but to actually re-impose its rules.
The eco-message gives this a contemporary edge that taps into C21st anxieties, but at the same time encodes the fragility beneath the ostensible confidence of Austen's own society which had witnessed the French revolution, the American revolution and was in the middle of the Napoleonic wars which take place unnamed in the background to her romances.
So overall I loved this and while it can certainly be read as light and frothy fun, it's actually quite literarily knowing and sophisticated, and requires us to simultaneously recall the original and forget it at the same time.