I think this is a great teaching tool. If there is a certain blend that my child is having trouble with, we can go to that page and find a lot of practice words. It has a nice progression from easy to more difficult. It isn't a 'sit down and read book', but it is great for its intended use.
Update, this book was very helpful for my son who had a harder time with some blends like "th" and "sh" and we were able to use those pages to practice.