I installed Firefox as my daily driver last year and have been completely happy with it. Great dev tools, good performance, and I agree with Mozilla's stance on privacy. All wins for me. I'll still occasionally open up Chrome for dev purposes -- but for the sake of browser diversity and maintaining an open internet, I encourage all my friends to give Firefox a try.
Just wanted to add a +1. I use FF with strict content blocking enabled which means that things like YouTube videos and captchas are often randomly missing from pages, as are images hotlinked from third-party servers. I see this as a feature rather than a bug and it's easily temporarily disabled if it causes an issue.
Of course, I use uBlock Origin as well.
Performance-wise I have no complaints and the sync across devices works just as well as it does in Chrome.
Energy usage would be my only complaint with Firefox. When I'm on my MBP, it does drain a bit faster (not horribly) when I have a few FF browser tabs open.
I suppose I should just use Safari when I'm not plugged in.
