If you're planning to walk the Coast to Coast, you'll want to buy this book. I walked the C to C in June 2004, using both the Hannon guidebook and Stedman. What's great about Stedman is the detail on his hand-drawn maps at tricky points on the trail. He shows you cattle grids, stiles, old fence posts and other markers, including paths NOT to take, and I often found the detail kept me from heading off on the wrong track. You can't find that level of helpfulness on the traditional strip maps that cover the C to C.
Also useful are Stedman's reviews of places to stay and eat on the path, and where to find things like ATM machines (the last one is in Richmond!). If you're thinking about walking the Coast to Coast, Stedman should definitely be in your mapcase.
That said, you wouldn't want this book to be your only guide. The maps extend only a few hundred feet either side of the path, so if you do get lost, this book won't help you figure out where you are. For that, you need OS Landranger maps. And the Hannon guidebook gives more general directions than Stedman. I found the two quite compatible, and used them both, Hannon to get me to the right area, and Stedman to negotiate the confusing parts.
Because Stedman's book is the most recent of the C to C guides, his information about what's happening in the villages and hamlets is current and quite useful.