I'm a huge Mr. Darcy's fan, and I would read anything related to it (not really, much depends), and I've read Pride and Prejudice more than once (in 3 languages), and have watched the BBC mini series (Colin Firth) and the 2005 adaptation more than 30000 times.
I never thought I would be reading Mr. Darcy's Diary; for I thought I would loose interest, and it might actually ruin my admiration for him, for I always thought he was mysterious and it's better this way.
I never read the continuations of P&P, I never thought I would, I thought they might ruin my imagination, and I LOVED P&P the way it is.
My sister's friend has brought the book, and my sister started reading it, unfortunately it was translated to Hebrew, and that was an excuse not to read it, since the translation always ruins the original, but still, I have enough curiosity to fail my ignorance. eventually I read it.
I read it, and while reading it I thought some parts disappointed me, but then remembered that i shouldn't have any expectations, and should consider this book as a fan fiction, like all other fan fictions, and should consider the effort the writer herself had done, and appreciate. I actually have found some amusing parts that made me laugh, smile and remember my huge love for P&P. Maybe if I read the book in English I would compare the level of the writing to Jane Austen. but unfortunately I didn't so I don't have anything to say concerning the style and writing, except that I thought it might be better if that wasn't a diary, for in a diary the main character keeps saying I a lot.
There are few things that didn't make any sense, and some characters were out of order. other scenes weren't as I imagined, and the feelings that Darcy shared weren't as I expected in some places. Mr. Darcy wasn't the Mr. Darcy I ALWAYS LOVED in P&P, neither was Elizabeth (I guess that was because of the different perspective of course). and did I mention, there was a lot of lack of creativity, not only in events in general, but also thoughts.
But still, it worth the trouble. and everybody wants to know more about Darcy. he is after all most interesting character in Literature (according to me at least).