Software engineers most of the time get fed by the company and i distrust, at least with my spending habits, the cost of consumer prices like clothing or gadgets being cheaper in europe than in the us.

Housing is the main difference: you can get a fairly large place in berlin, and you can have a family there. But SF is one city, there are pleny of other cities in the us more family friendly (if not any other city).

I remember recently a map showing the purchasing power by salary per state, and the biggest purchasing power was nebraska.