I disagree with the thesis of this article from the Physicians Committee for Responsible Medicine, and I am curious to hear thoughts from others.
https://www.pcrm.org/news/good-science-digest/persistent-issues-journal-nutrients-and-its-publisher-mdpi
The article claims that the APCs in MDPI journals results in lack of scientific quality, that MDPI journals self cite, and that MDPI is predatory. The article focuses on Nutrients, but implicates the entire publisher as well. I tend to disagree with these claims based on my own experience with this publisher.
Regarding the self citation issue, I find the idea ridiculous. The authors are independent actors, the publisher has no hand in what the authors choose to cite. Further, the journals within the publisher are not a single entity, each journal has it's own editors and research focus. I don't see how it's an issue if authors from an article from 1 MDPI journal cite another if the research is relevant.
Regarding the quality and predatory claims. we have published plenty in MDPI , including in Nutrients, and the peer reviews were thorough from my personal experience. Additionally, I have reviewed at least 23 papers from MDPI. I am very thorough, and find that I reject 40% of the time and request major revisions the other 60%, trying to maintain strict quality control with respect to the methods and legitimacy of the results. My rejections are almost always taken into account, in one recent case the academic editor of IJMS (international journal of molecular sciences) rejected based on my review report alone (due to serious methodological flaws) without any other review reports being submitted (there are usually at least 3 reviewers per article for this journal). The times it's not immediately rejected during the first review report (due to discrepancy in recommendations from other reviewers), it is often rejected in later reports if the issues are not addressed. I assume there are bad experiences from others, but that's likely true with any journal and publisher.
As I said, curious to hear thoughts