It really depends on the journal though.
Why not?
some might regard it as a predatory publisher
Mostly it’s seen as low quality no?
The vibe I got was that they’d basically accept anything in return for money.
this is my impression. back when i still was in academia it would pop up from time to time but i never published there since i never cited any of their journals in the first place. (why would one publish there when all your peers are somewhere else). nowadays i sometimes get requests from them to my personal email for special issues which i just ignore. (it’s academic spam essentially).
have a look at retraction watch https://retractionwatch.com/?s=mdpi
I’ve seen some really good papers in MDPI which challenge the consensus in different fields and I’m assuming aren’t published in bigger journals because colleagues are stuck in their own ways and disagree with the premise of the paper.
But these papers are vastly outnumbered by a mix of low quality papers and obvious corporate sponsored or “self-promotion of my new vitamin” type papers.
Thanks. It’s been a long time since I left academics. I can’t remember having heard of them before.
Inexperienced myself also served as a guest editor for one of their journals. Won’t happen again.