I really wanted to give this book like 3.5 stars, but I figured I'd round down instead of up since everyone else is praising it. First off, I did find many of the articles interesting, particularly the article about "Insiders vs. Outsiders." And the comical, albeit cheesy, faux-college-essay describing why Xander is the M.P.I.F.F.G. (Most Powerful Individual Force for Good) was also enjoyable and thought-provoking.
Those points aside, this book seemed to endlessly repeat itself. The first time someone explained why Angel, Riley, and Spike were bad partners for Buffy, it was quasi-interesting. By the third or fourth times, it was a broken record. Each author might add a slightly different take, but it was all basically the same. The book is littered with many other repeated themes that make the book not as fun to read as it could have been. Also, with the exception of the introduction and the Xander Essay, this book can be very dry at times. This is a shame, because the humorous intro and Essay are over within the first 20 pages, and the rest can be dense at times.
The thing that really surprised me was how many small errors there were in this book. It really seemed like no one ever proof-read this book before sending it to the printers. One of my major beefs is an author who claimed to be a huge fan referring to Machida (the snake demon from Season 2's "Reptile Boy") as "Mikusa." This is just sloppy work, and a real fan would have taken the two seconds to look up the demon's name online if they weren't sure about it.
The bulk of the errors are in the numbering of the episodes, and the fact that episodes may be credited as happening at multiple times. Depending on what you read in the book, the episode "School Hard" was either episode 2-3(which it was), 2-5, or 2-15. And the "Becoming" episodes, which were episodes 2-21 and 2-22, happened either in the second season, the third season, or the sixth season. And one of the times "Becoming, Part One" was in the third season (3-21, it was called), Jenny Calendar was still alive (even though she died in 2-17...or as that author would have said, 3-17). And occasionally, it just seems that the author of a particular piece, and the (possibly invisible) proofreader were just lazy:
"The second-season finale is titled 'Becoming' (3-21, 3-22)..."
If you can get this book at a library, I won't try and dissuade you from checking it out, because it does have some interesting ideas and doesn't talk down to you. However, its redundancy and errors keep this from being a book I would even give 4 stars to.