When I was taking music classes in university, I had a professor who opened my eyes to the importance of careful editing and scholarship in regards to music publishing. He was a Bach researcher and harpsichordist, and he had been the editor of a $30 printed edition of the Well-Tempered Klavier. To explain why this edition was worth the money when there were so many free versions out there, he went through each piece and pointed out how many different versions there were (which to pick?), how the originals got mangled over the centuries as each editor added their own "corrections", how there were occasional ambiguities in the score, and so forth. I learned that there was no "the" Well-Tempered Klavier at all; it was history, and as such, required a trained historian to piece together in the most authentic way possible.

Unfortunately, most people aren't aware of this. It would be a shame to lose some of the nuances of the composer's original intent because of, essentially, propagation error.

I wonder how this edition fares? (I don't have my physical score to compare, sadly.)