Overall, pretty decent. The layout of the book is fun and easy to read, designed to help you skip around. The recipes are approachable, not a lot of extremely expensive/exotic ingredients. Anyone with a Wal-Mart or decent size grocery store could put together the recipes. It also has a great balance of breakfast/snack/dessert/meal replacement recipes.
I haven't really tried it as a "diet", so I can't talk about weight loss. I'm on a medication that can absolutely kill your appetite, and sometimes I have to force myself to eat. The feeling is similar to trying to eat on an already full stomach, kinda makes you feel queasy and gross. But, you can't not eat, so I tend to reach for a lot of soups, smoothies, and other liquid meals. So if you have a kid that just will not eat, or someone who has a difficult time eating enough to stay nutritionally satisfied, this is a great book to have around.
The only reason I gave 4 stars instead of 5 is because there was a good chunk of blogger-ish filler. I wasn't really expecting that, I thought this was more of a straight up nutrition/recipe book. So there was a lot of focus on the authors and their family's side stories that didn't really contribute much to the book. There were also some surprisingly churchy passages that took up page space but weren't relevant to the subject matter. It is still mostly recipes and nutrition talk, but they probably could have cut out a good 15% - 20% of the book and made it even better.