Also, my office PC (Windows 7) is now on the Firefox 57 beta and it's ... really garish and ugly looking. Switching the layout to Compact and the theme to Light helps a little with the tab bar, but the KITT loading tab animation is distracting, the icons manage to be intrusive and bland simultaneously, and the new logo is a bad LSD trip (to say nothing of the fact half my extensions stopped working, and while I knew that was coming, most of them have no replacement because the APIs don't yet exist). While I thought Australis was a step backwards in terms of utility, at least it had some design consistency. Photon, on the other hand, is all over the place and it's an unwelcome change on top of everything else. I'm almost afraid to update Firefox on the MacBook Air.
But, to be fair, it is palpably faster. Much faster. I certainly can't argue that. Nevertheless, the compromises made are such that if it weren't for Google's relentless commitment to snoop on everything I do, I have to candidly say I'm not sure I'd be sticking with the new Firefox.