Fools and Their Foolproof Workflows --McIlroy

The Seybold study segmented its audience into "PDF Receivers" and "PDF Generators," with a much higher response rate from generators. GATF, albeit with a smaller sample size, focuses exclusively on the receivers, mainly commercial printers and prepress shops.

Some of the questions, naturally enough, were the same (or very similar) and it's worth comparing the responses from each survey.