[light_hue_1]

There are reasonable MDPI journals, and reasonable Frontiers. Just like there are predatory IEEE journals and conferences.

You can't just look at the publisher.

A quick shortcut is to look at who are the editors/organizers. If you don't see affiliations from the West, it's unfortunately a very bad sign.

[PaulHoule]

... and plenty of ethical problems in terms of the very business model of Science, Nature, Elsevier and all that. Not to mention what they've done to maintain their comfortable position.

MDPI is the most active RSS feed by far in my collection, they publish a lot of stuff. I'd be interested in getting feeds of Open Access papers on other journals (say from Science) but so far no dice.