I am a Huge fan of Buffy the Vampire Slayer. I watched the series premier when I was a child and was a loyal fan right until the drawn out end, the witty lines and emotional ties to the characters made it one of the most entertaining elements of my childhood. But this review isn't about the show Buffy, its specifically about the box set as an item to purchase.
When I bought the box set (over a year ago now prices may vary) it worked out to be almost exactly the same as buying each of the seasons separately on DVD. The reasons I went for the box set were simple, it was convenient, rather than search the shops for each one of the seven seasons, they were all there neatly packed in a box for me (The fact that the tin was a nice red colour factored into it aswell).
Upon opening the case you find inside the seven season DVD cases, and a small book which contains a list of all the episode and also tells you which are Joss Whedon's favorite episodes of the entire series. He offered interesting opinions, and it would be a good read for anyone who's a fan of his personally, as well as the show. unfortunately as soon as you turn the pages of this little book, they peel right out, the glue doesn't hold at all so be gentle if you want this item to last.
I was really disappointed to find out that even though this particular box set was only just released recently (May 2009), none of the seasons had been remastered. I was watching buffy in the same fuzzy quality as I did in 1997. And if you're looking for mega amounts of special features then don't look here. You would think that over 7 years of shooting they would have ended up with more cast interviews and other interesting bits and ends, but the main thing found in the special features are episode commentaries by various writers for the show, and you usually only get 1 of those per disk.
Overall the box set doesn't offer you anything different, or interesting or special besides the tin itself, which at least keeps the dust of the DVD cases. So if you went out and bought them all individually, don't worry, you're not missing out on anything.