I've been wondering this for a while.
I'm currently doing the first year of my PhD in Frankfurt. Originally from New Zealand.
I'm not complaining about my situation but if anyone asks me I'll honestly say I would have preferred an English-speaking country.
I'd actually applied to about 9 PhD programs in the US and all rejected me. Yet I was accepted to a (supposedly far more competitive) fully funded European PhD, and rather quickly - accepted late last year and already working now.
It has me wonder. I had very strong letters of recommendation from professors that are well known in my field. I had also published a paper (which has now been cited in Nature) out of the fruits of my research Master's.
My GPA is about 2.8-2.9 by US standards (hard to convert, my school was a "we grade harshly, rarely give out As and we'll make you sweat for a B" style system). Professors at home told me my grades were irrelevant with the strong letters.
People say that I was likely discounted because I had a research master's already and I'd probably see doing more course load as beneath me? That doesn't seem to hold water.
I really don't know. Any thoughts?