{Full disclosure: I'm an open access advocate working exclusively with organizations that are working to accelerate the adoption of Open Access to all scholarl

{Full disclosure: I'm an open access advocate working exclusively with organizations that are working to accelerate the adoption of Open Access to all scholarly journal content. MDPI is one of my clients} Your "quick google search" is likely to have picked up disparaging comments initiated in large part by having been listed for 18 months [from February 2014 to October 2015] on Jeffrey Beall's list of potentially predatory publishers. On October 22 of 2015, Jefferey Beall himself tweeted the news that they had successfully appealed their inclusion on this list and that he was taking them off of his list. https://twitter.com/jeffrey_beall/status/659321914582679552?lang=en https://twitter.com/jeffrey_beall/status/659321914582679552?... "Jeffrey Beall ‏ @Jeffrey_Beall MDPI removed from publisher list following successful appeal. #OA #MDPI 3:52 AM - 28 Oct 2015 from Denver, CO". Nevertheless this episode remains prevalent on such sites as Wikipedia. MDPI does not engage any of the professional "reputation management" schemes that might fight all the ways which those 18 months on Beall's list continues to crop up in various places on the Internet. They focus instead on the interests of academics who publish in their journals by providing excellent peer review with unnecessary delays taken out of the process. They are an exclusively Open Access Publisher. They have almost 200 journals and have published exclusively open journal content since 1996. Many of them have impact factors and participate in Web of Science. All of their established journals are given the seal of approval by DOAJ (The Directory of Open Access Journals), and they are members of COPE (Committee on Publication Ethics) which did a specific review of their operations as part of MDPI's appeal to be removed from Beall's list. I'd suggest in deciding whether or not to do peer review for any specific journal of theirs: look at the editorial board and particularly at the editors-in-chief. Are they respected people in your field? Contact them directly if you have any doubts. All decisions whether or not to publish articles submitted to them are made by members of the editorial board under the guidance of the editors-in-chief. So that should be the measure of whether or not the journal is meeting your sense of what is high quality in your discipline.