Of the original 5,000 copies of the first edition BOOK OF MORMON that were printed in 1830, only about 500 copies have survived. Over the past twenty years, I've either owned or handled about 150 of those.
From my experience, if all first edition copies of the Book of Mormon were rated on a 1-10 scale, the results would look something like a "bell-curve". By extrapolating the results of my own ratings--which are based on my viewing almost one-third of all surviving copies, I would estimate that about 300 of these 500 copies would rate somewhere in the middle--as "4s", "5s" and "6s". These copies, which are typical of the majority of books that show up on the market, are textually complete, the covers are well-worn, and the original label on the spine if often missing or the gold lettering on the black label has disappeared. These copies may also have a few torn pages and show signs of damp staining.
I would estimate that about another 100 copies would be in much worse condition. These copies are often missing the title page, show damp staining, lack all or part of the original binding, and have various missing pages.
On the other end of this "bell-curve" are the "100 Finest Surviving Copies". These are copies that I would rate as a "7" or above.
These copies have the original binding, title page and label on the spine. The "BOOK OF MORMON" is still visible on the black, red or tan label. The text block is tight and square. The original binding is present. And the pages show less foxing (brown spots) than the previously mentioned copies. There are probably 60 or so books that would rate a "7", about 25 that would rate an "8", about 10-12 that would rate a "9" and in my opinion, there are only 2 or 3 copies that could claim the distinction of being an almost "perfect 10".
I've had the fortune of owning two "almost perfect 10s". Peter Crawley (author of A Descriptive Bibliography of the Mormon Church) saw one of these copies and said that it was the finest copy he had ever seen. He had originally seen the copy that I acquired in 2010 almost forty years earlier in Northern California. I've had one other comparable copy. These "almost perfect 10s" have a nice honey-colored original binding, the "blue speckled edges" are vibrant, the label is crisp and clean, the seven double bands in gilt are present, the text block is tight and the corners are square. There is little to no foxing, and the front and rear end sheets are present. These copies show just enough age--yet maintain all of the important distinguishing characteristics of a first edition Book of Mormon.
I've attached a photo from the label of this "almost perfect 10" copy of the first edition Book of Mormon. http://www.pinterest.com/pin/164662930098037457/