I've been reading several of these diary-style books based on Jane Austen's works, as they come available for free download.
Thus far, this is my favorite of the expanded Austen books. It's very well written and gives the shy sister of the Pride and Prejudice hero Fitzwilliam Darcy an eloquent voice. The author does a fantastic job of putting us back at Pemberly, recreating the feel of the time. While the author makes no attempt to recreate the literature style of the time, the modern writing style doesn't detract from the story.
If you enjoy Jane Austen's works, I recommend you give some of the many books that expand the Austen tales. This is one of the better ones in my opinion.