We were just getting some revised ebook editions of our books on line (the great thing about a POD approach is that anything can be fixed, anytime) and began to wonder if there was any point in offering PDF versions. We have always done this as a matter of course, along side the print and epub editions (and the Kindle variant that shows up at Amazon --- they convert that from the epub). But the PDFs do not really sell.
It is not that much trouble to create them, understand, a few very minor changes from the print edition (margins slightly altered, ISBN removed, cover added). But it is an additional chore and perhaps for no reason. For now, we do not intend to change our procedure and will continue to offer the PDF online --- at book shows and so on, we have been including it in a bundle with the epub and/or print books.
Thinking out loud here --- anyway, PDFs of most of our books are available at our 'spotlight store' and will continue to be. Now we need to start thinking about audio books!