[neogodless]

This is an interesting comparison. I'm using uBlock Origin so I'm not sure how the ads compare. Layout-wise, theconversation.com is a little more narrow, and the links are not as highlighted. But the non-black font is a deal-breaker for me. (I'm sure there's an extension, but I find myself doing Inspect -> Uncheck Font Color a lot!) The only other difference is that PopSci.com seems to have less clutter in the columns, so for me, it's the better reading experience (before I give up and toggle reader view!)

EDIT: There is (at least one!)

https://addons.mozilla.org/en-US/firefox/addon/blacken/

[adrianmonk]

Another difference is that with The Conversation, when I scroll to the bottom, I get a dialog that says, "Get The Conversation’s newsletter to understand the news" and "Subscribe now". Popular Science doesn't seem to have a dialog like that.