I can say we did this really well with Lucy, and we were a little more lenient with Adam, but it works, and we got sleep, and so did the kids. They both grew and ate well as infants.
In my experience, the people that criticize the book haven't actually read it. It was recommended by several family members and friends, and Pete and I think its pretty logical. It contains a lot of good practical advice from baby's first day through over a year old. I will be referring to it quite a bit, once again, in just a handful of weeks. Nine more weeks til due date!