I've bought this book after researching many authors of other 5:2 diet books (there are soooo many out there!)
The main difference is that the 2 fasting days are recommended to be taken consecutively, thus giving the body a proper chance to detox and clear the palate. It also ensures that you do the second fast without loading up on carbs in between.
I find this method a good one; I make a huge mixed salad of leaves, grated carrot and beetroot, chopped spring onions, celery, cherry tomatoes, mint, dress it with a few drops of Balsamic vinegar and oil, then use it for 2 meals on each fasting day. I top it with either dry-fried salmon, hard-boiled egg, wafer ham or cottage cheese - all recommended as foods on fsating days.
I hate having to count calories and you don't need to on this version; you simply eat the recommended portions of recommended foods each day.
I am finding that I crave simple, tasty, healthy foods on my non-fsating days as well - nothing manufactured (OK, the ham was packeted, but in future I shall cook my own gammon.) I don't feel hungry, I have energy enough for my daily dog-walk and I think it will work!