These books are much higher quality than the standard release strategy guides.  Obviously the books are hardbound allowing them to be more durable, but also the pages are printed on 80lb paper so they are thicker more durable pages than the original magazine releases.  The material has also been revised from the original print so they are the most complete and accurate of the guides to date.  I just received my guides recently and I have copy number 49647 of 50000.  When these are gone Prima has said that they will not be reprinted.  They have also released a collector's guide individually for A Link Between Worlds that I grabbed as well.  Again the quality of the information inside is excellent as is the quality of these books that will surely become collector's items.  Here's hoping they also release books for Majora's Mask when it inevitably releases on the 3DS as well as the new Zelda adventure for the Wii U later this year or Spring 2015, whenever it is ready.