Person who pays the bill here. Latency does matter and we're paying an additional $1.5k new in Feb to improve european latency. RubyCentral can afford to spend the money to improve latency issues, so we do!

That's been my impression so far with repositories where you configure a mirror explicitly, like Debian or CPAN. I used to be diligent about doing "the right thing" and switching out the default (usually something in the U.S.) for a Danish or nearby mirror. But I've stopped caring much because it doesn't really seem to make any perceptible difference. If I remember to, I still will switch it just so I don't unnecessarily waste intercontinental infrastructure, but it doesn't make much difference to my own experience.