I also purchased the sticker book and went through the packs with my little cousins, having plenty of fun putting the stickers in the book. We had two full sets of figures and plenty of spares, but they make great action toys for little superheroes.
The only thing that I would complain about is that you are not guaranteed a full set of stickers. We had a lot of double ups on stickers so we weren't able to fill up the sticker book. Apart from that, considering how cheap it was to buy, it was worth the entertainment value for both the little kids and this big kid.
I picked up two boxes of the sticker & figure sets as well as one of the albums: http://www.popcultcha.com.au/batman-the-dark-knight-collectible-sticker-album.html
For under $20 that got me a complete set of stickers for the album (bear in mind you might not get them all though due to doubles - I did though!), heaps of spares and 48 mini-figures. How can you argue with that?!
The figures are decent quality for the price - approximately 5cm tall for most and the paint applications are OK. You're getting 24 figures plus 192 stickers for under $10 so the value is definitely there!
Grab an album and a couple of boxes of the sticker/figure sets while they're going cheap.