This is glorious stuff and it's wonderful to see. I'm thoroughly enjoying digging into those old Famous Monsters.
I should add, though, that while reading online is neatly high res, most of the downloadable formats are not. Just look at the file sizes (or download and see for yourself).
If you want to download, skip the PDF or the other options listed on the left side of the page, click HTTPS to list all files and download the CBR.