Ed,
Some may choose to publish in MDPI journals rather than elsewhere because quality control can be so lax that rejection is unlikely; moreover, even if the quality of one’s paper is shown by “post-publication peer review” to be extraordinarily poor – and its main conclusions wrong! – MDPI will not retract the paper: http://www.australianparadox.com/pdf/RRsubmission2inquiry.pdf
That sort of arrangement might seem attractive to industry-friendly scientists with strong opinions who don’t mind wearing a second hat as MDPI’s “Guest Editor”:
http://www.mdpi.com/journal/nutrients/special_issues/carbohydrates http://www.mdpi.com/journal/nutrients/special_issues/sugar-obesity
