Cameron Neylon responds to the allegations that PLoS is a pay-to-play vanity press:
That an author pays model has the potential to create a conflict of interest is clear. That is why, within reputable publishers, structures are put in place to reduce that risk as far as is possible, divorcing the financial side from editorial decision making, creating Chinese walls between editorial and financial staff within the publisher. The suggestion that my editorial decisions are influenced by the fact the authors will pay is, to be frank, offensive, calling into serious question my professional integrity and that of the other AEs. It is also a slightly strange suggestion. I have no financial stake in PLoS. If it were to go under tomorrow it would make no difference to my take home pay and no difference to my finances. I would be disappointed, but not poorer.cameronneylon.net, Science in the Open » Blog Archive » In defence of author-pays business models, Apr 2010
You should read the whole thing.