I'm enjoying Zen, really gets out of your way nicely. Does a bunch of things I used to hack in userChrome.css better, still reasonably secure as best I can tell, it's not librewolf but it's still firefox so I add back the normal privacy add-ons, about:settings etc, but the UX uplift is worth it.
That said, without the firefox base we're all fucked, so this, and their general culture, is really quite disturbing.
Flip up ones, as long as you're not vain (which you aren't with clipons anyway), solve this problem nicely. Go for polarized, oleophobic too...