I purchased this based on the reviewer who claimed to have compared this with the much more expensive Wilton-Ely edition ($300) who said he could barely tell the difference between the plates. Since I had a small Taschen book, and did not like how the illustrations seem to "wash out" or how the engraved lines became all darkened and mashed together, I ordered the $40 version based upon the reviewer's word. When I received the book, however, the plates were absolutely NO BETTER than the small Taschen version; they are just blown up. So be warned: you will NOT be getting higher quality photos of the engravings/etchings. The same washout/blurring is to be seen in the larger (not so much larger either, btw) plates in this more expensive volume. The problem is, the etchings were PHOTOGRAPHED with a low-quality camera, and therefore were not able to get all the detail, no matter how big they are blown up. I have no idea what the Wilton-Ely version looks like, but my guess is they are not simply photographic plates, but graphically reproduced engravings/etchings, where ALL the engraved lines show, which explains the hefty pricetag. But I could be wrong.
However, since the plates ARE larger, you don't need a glass to see them, and the 2-volume set does include all Piranesi's etchings, so for this I'm giving 3 stars. Oh, yes there is a very strong odor reminiscent of oil-based paint; imagine you're looking at this book while in a room full of painters work with solvents! This odor is not likely to dissipate. Still, a very handsome set and a bargain, really, at $40.