I give this 5 stars because its one of very few DnD books by Wizards of the Coast that's come out in the past two years that I read from cover to cover. It interested me. A lot of the other titles they've released lately have been the sort of material you pick and choose; sometimes avoiding large sections of altogether, like the race books they released earlier this year. So I guess I'm rating in comparison to other DnD books.
It's not the most amazing or ground-breaking stuff, but it's a different take on the game than most of us choose to use. I guess it was inspiring to me. I've been DMing now for about 20 years, and though I've done a lot of what's in this book on my own at times, I really enjoyed reading it, and I think this book needed to be produced for those who want to run a battle based campaign and didn't know where to start.
A warning, though. If you're looking for feats, races, classes, prestige classes, etc.... this is not that type of book. That being said, I'm glad. Most other DnD books of late have been only those things with a little fluff to make it all part of a theme. This book is good for any DM.