1) one coworker who moved from the bay area to the midwest
2) another coworker evaluating NYC vs other potential places to live in the US
it seems like what Mozilla pays doesn't differ that much across their different US geographic salary bands. Both coworkers found it would be more favorable for them to take the small pay cut in exchange for a dramatic cost and quality of living difference.
And yes, someone from Mozilla confirmed here some time ago that they do differentiate salaries based on the country/region - they won't pay "US salary" to someone in Ukraine for instance.
I work for a big US company in the UK in a senior role and I get $150k approx. I work just outside London but I regularly have to attend meetings right in the City.
I'm going to move to Mexico before Trump gets his wall!