Excellent as a companion to the region, and (curiously) better than the official Snowdonia National Park guide at giving a feeling for the place. For me it is a definite advantage to have the whole of North Wales covered in one book, and I would have been happy with even one or two more walks from the outer regions (the north-east especially). The photographs are highly atmospheric, and there is a generous selection. They really make the book treasurable.
The downside is in the route maps. They are certainly sub-standard, and can only serve as a guide to finding the route on a detailed hiking map (and only with the help of the written directions). But even with guides that give you extracts from Ordnance Survey or Harvey maps, it's still usually worth having the separate whole map so that you can see the wider context of a walk. Only, you'd have to buy a lot to match this book's coverage, so some concession should have been made to the walker who only wants to buy maps for their favourite places.
Also useful to me would have been extracts from wider scale maps that are good enough to show shaded relief, one for the whole of North Wales, and others (more detailed) for each region covered, so that you can see exactly how each walk is placed in its wider landscape. That should also help in planning a trip, making it easier to link up separate walks. Maybe a good road atlas is enough, but it's nice to have this sort of orientation in your guidebook, too.