These scans are nice, although since they are derived from an analog (non-digital) work, they do not look as good as the modern (digitally published) books do. However, having said that, I think these scans are about as good as you're going to get with current technology, and when I did a test print (I printed page 4 of the first book, "Eastern Oerik in Relation to...") and compared it to the actual 30+ year old book that I still have in my "vintage" D&D collection, and I couldn't tell the difference. Bravo!
As for the maps, when you zoom in on them, they are very clear at both 200% and 300% magnification, which is perfect for just about any game-related purpose. You can easily make out place names, map markings, and hex borders at those magnifications. Again, these maps were originally analog (paper) entities, so you can see the flaws (creases in the paper, slight printing imperfections, etc.) but these flaws are MINOR, and are EASILY overlooked, considering how useful the famous Darlene maps are to us Greyhawk aficionados.
The file sizes are small (10, 13, and 10 MB, respectively) which is great for being able to import them to a mobile device. (I have them on my iPhone 5.) That's the best thing about any PDF book, is the portability; I used to carry around a big, heavy, dufflebag full of D&D books. Now, I just whip out either my phone or my iPad, and BAM, I'm good to go.
Overall, these scans are superb, and for $9.99, you cannot go wrong. Hooray for DnDClassics! Great job!
[5 of 5 Stars!]