Personally I take my security and privacy over performance any day. Firefox by default better protects my privacy, and it customisable where it doesn't. Add to this uMatrix, uBlock and disabling JavaScript I'm good for security.
I don't care much about negligible performance stats. I notice little difference, especially with the above mentioned add-ons/settings. The websites they break I don't care much about or allow on a whitelist basis.
Bad as Mozilla is I trust it more than Google, especially in regards to this thread and others currently floating on the front-page.
But say what you want about their privacy practices, Google is as strong as it can get on security front.
Not really. Maybe ~6 years ago but they've made insane progress. Full site isolation is rolling out now and the performance is great. Definitely faster than Chrome on my laptop.
The organization that overpays managerial people, fired technical talent, and funnels donations into political causes instead of browser development is not much better either.