Might be a coincidence, but they also just announced plans to rent 50'000 square meters of office space in Zurich http://www.handelszeitung.ch/unternehmen/google-investiert-d...
I wonder why is Zurich a big part of Google's strategy as opposed to other places in Europe
Just a guess :)
EDIT: It seems Vienna is on top since 2010, my bad. But position 2 is not so bad, and the other points still stand :) https://en.wikipedia.org/wiki/Mercer_Quality_of_Living_Surve...