The PDF files can be copied to your hard disk and printed out as needed, so the CD works in Windows, Mac OS and Linux. For some unknown reason, however, printing from Linux is extremely slow. The advantage of printed sheets is that, unlike with a bound book, the pages will not turn by themselves while you are trying to play. (Of course, a gust of wind could be a problem. Luckily, all the pages are numbered, and most have the title on every page).
The quality of the PDF files is somewhat variable. The files are 1-bit
thresholded images from a scanner. While most of the printouts are clear
and readable, others (such as the Partitas) require a great deal of manual
fixing up--for example, accidentals and note stems are sometimes too faint
to read. For example, here is an enlargement of a few notes from the
Goldberg Variations in the "piano" CD:
The image above is an unprocessed screen dump, not a scan from a printout, so the jagged curves and missing lines are in the original. Bear in mind too that the print size from most printers will be only 8x10 inches, which can make reading it very hard on your eyes. Finally, especially for a beginner, the notes will seem very dense and close together. In contrast, the files on the Bach Cantatas CD (J.S. Bach: The Complete Church Cantatas) are larger and much easier to read. Despite these minor problems, however, these two CDs are a tremendous convenience and highly recommended, as long as you're aware they're not perfect.