Not GP, but I decided to try Firefox again last week, and had to give up because I couldn't navigate to intranet URLs without explicitly typing http://
Strangely foo/ works (goes to http://foo/) while foo/bar does not (instead does a web search for foo/bar).
It's these sorts of things that make me realize that people just don't care about the health of the open web, or about protecting their privacy.
Ultimately this is a super minor issue (and turns out there's a way to fix it, per the sibling comment), but everyone just has their own pet excuse why they "can't" change to a browser that is objectively better for the web in every way.
Just to be clear, I think having to prefix my web searches is not a fix, but rather an even greater inconvenience. I'll either have to type "http://" dozens of times per day, or "g " a hundred times per day, for no discernible reason.
Aside from that I don't think Firefox is particularly good for the web. Their license is no better than that of Chromium, and Chromium has proven time and again it's a good starting point for a fork.
Mozilla employees are paid with search ad revenue, to an even greater extent (95%) than the subset of Blink developers employed by Google -- so their incentives aren't even any better.
Strangely foo/ works (goes to http://foo/) while foo/bar does not (instead does a web search for foo/bar).