Open Access publishing does not affect peer-review
Choosing to publish in an open access journal or deposit your work in an institutional or subject repository has no impact on peer review; in fact, open access is entirely independent of peer-review. Some people worry that because many open access journals charge a fee for publishing, they might choose to accept more papers, but of lower quality in order to increase their revenue. However, the same argument actually applies to subscription publishing: journals could grow in size or frequency and raise subscription prices. This does not happen with subscription journals or with open access journals as it is not a sustainable model: the journal would quickly gain a reputation for poor quality and fail.
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Suber, P. (2007). Open Access Overview: Focusing on open access to peer-reviewed research articles and their preprints. http://www.earlham.edu/~peters/fos/overview.htm
Suber, P. (2004). Objection-reply: Whether the upfront payment model corrupts peer review at open-access journals. SPARC Open Access Newsletter, issue #71 http://www.earlham.edu/~peters/fos/newsletter/03-02-04.htm