Kaer Maga - City of Strangers is one of the best setting books of any game that I read in the last several years.
It is PACKED with great ideas, odd little facts, adventure hooks, interesting organizations ....
The writing is superb and the locale would merit a much more detailed treatment like one of the classic box sets from the early 90ies - owing to its format the book falls a little short on art / mapping and in many cases more detailed elaborations would have been great. Sadly, that will probably not happen. Still: Get this book!
The map is not only much darker than on the product images (which are already kind of dark in this case), not only too dark for dry erase markers to be of any use, but its actually so dark that its really hard to discern the details of the pictured forest scenery AT ALL.
Ok, that last statement was a slight hyperbole - the map is certainly somewhat useable, but you'll need good lighting, and as I said - forget about dry erase markers.