I've been a happy Conkeror user for years. Recent changes to Firefox seem to have broken it, so I'm sticking with the older version for now. Chrome/IE/Edge/Safari/etc. aren't FOSS so I don't touch them.
Firefox and Chromium are getting increasingly slow and bloated, plus their chrome takes up a bunch of screen space, doesn't follow the system theme particularly well, and they rely far too much on the mouse (there are extensions which help, but they're still not particularly good).
Out of the two I would still recommend Firefox over Chromium, since Mozilla seem more ethical than Google, contribute less bloat and churn to Web APIs, etc.
Firefox and Chromium are getting increasingly slow and bloated, plus their chrome takes up a bunch of screen space, doesn't follow the system theme particularly well, and they rely far too much on the mouse (there are extensions which help, but they're still not particularly good).
Out of the two I would still recommend Firefox over Chromium, since Mozilla seem more ethical than Google, contribute less bloat and churn to Web APIs, etc.