The service comes in several levels, here is pricing info. The most basic scan for books is a dollar per 100 pages, which seems pretty cheap. OCR (real text), angle correction, and other quality options are extra.
I know that many people, myself included, find it genuinely difficult to read paperbooks after getting used to ebooks (some even get headaches). So if there are books you just must read, but nobody has digitized them yet, this might be a solution.
Getting your whole library, if you're a bookworm, scanned in good quality might cost a pretty penny though.
I asked them:
I suppose the customer always is the one to ship the book (if you don’t have it)?
Are the scans real, searchable text?
If the customer adds OCR by request, then the scan is searchable. The quality of the OCR depends on a few things, like the quality of the book, language, fancy font, etc. (if they ask us to do angle correction on the file after or scan
at 600 DPI it's a lot better). But the average book is fairly accurate.