The Economist says:
"Tens of thousands of asylum-seekers flowed towards Germany by rail, bus and on foot, chanting “Germany! Germany!”, to be welcomed by cheering crowds. Germany is showing that old Europe, too, can take in the tired, the poor and the huddled masses yearning to breathe free. It says it can absorb not thousands, but hundreds of thousands of refugees.All of this would be very compelling if the social capital represented by the incomers was at the same level as or, better, superior to that of the present northern European incumbents. The Economist thinks (or pretends to think) this is a non-issue .. but unfortunately, it's not.
Such numbers will inevitably raise many worries: that cultures will be swamped by aliens, economies will be overburdened, social benefits will have to be curbed and even that terrorists will creep in. Anti-immigrant parties have been on the rise across Europe. In America, too, some politicians want to build walls to keep foreigners out.
Yet the impulse to see migrants as chiefly a burden is profoundly mistaken. The answer to these familiar fears is not to put up more barriers, but to manage the pressures and the risks to ensure that migration improves the lives of both immigrants and their hosts."
This is what the UCL guy who looked at the evidence had to say.