This edition is invaluable to any researcher of Jane Austen's work or time, and is ridiculously pleasing to footnote fiends. There's almost as much annotation as text, and it's on facing pages in full-size type.
If you haven't already read the book, you probably shouldn't start with this edition. Not only are there spoilers, but the glut of information will overwhelm your enjoyment of the story. But if, like me, you have Austen memorized, you NEED a copy of this book.