Virginia Steel, UCLA University Librarian, has released "An Open Letter to the Academic Community."
Here's an excerpt:
I fully support the laudable goals of all members of the open access movement and am proud to count myself among them . However, I feel quite strongly that the mechanism OA2020 proposes to achieve those goals [article processing charges] would not be workable across the broad international spectrum of research institutions, funding bodies, and publishers. Based on the limited amount of research that has been done to date, the model appears likely to cost more in both the short and longer term, making it as financially unsustainable as the current system.