The quality of the PDF is very good. Each of the maps is available both in a one-page version and a 4-page version for printing on 8.5x11 paper and taping together for a nice 17x22 version. These are clearly not scans, they're digital files that were put into PDF form, so there's no scan problems at all, basically pixel perfect.
Note that they are black and white.
I knocked off a point for the content... mostly because whoever drew the maps made the really bad decision to make the water light gray and the forest dark gray. Maybe the originals were in color, so the blue vs. green made it look fine? I don't know, but in these, it took me a long time to realize the "ocean" I was looking at was labelled as a forest. It's really unfortunate, since this is a cheap way to get all 18 huge maps of the wilderlands.
Also note, since you can't see in the preview, these are updated maps, not the old-school maps. This is unforunate, since I think the old maps had a lot more character... but obviously weren't available in any kind of digital form in 1978 or whenever it was they were published.