One notable barrier that has prevented faculty from adopting OER is concerns about the quality of the materials. The present study extends upon a growing body of research indicating that OER are not perceived to be lower in quality than traditional textbooks.
I have trouble believing many faculty members will be swayed by undergraduate students' perceptions of quality. There's a difference to be explored in "quality of disciplinary content in the abstract" vs. "quality as a study aid for this particular course."
This is of course a broader concern for advocacy for OERs, not a critique of this particular study.