How much migration in Europe is good migration?

We have seen there there has been a rise in anger towards migrants- since the Syrian crisis aggregated and hundreds of thousands of migrants started arriving in Europe with increasing and unprecedented numbers. The anger and fear of migrants was always an issue but has become more mainstream in the last few months. But how much is it transitory and illusion and how much justified?

It is important the crisis is discussed in an open and fair manner-especially in its dimension of number and impact of migrants on Europe. What do they bring to Europe and what is driving force that is bringing them to Europe.

There is a need to discuss this in it's full scope- legal and illegal migration/asylum seekers ,economics, political and cultural impact,pan Europe impact and on specific countries,short term and long term.

We have had some problems in a similar topic recently so it will be great if discussions are more civil on this thread. Please refrain from personal attacks-both open and veiled. A good starting point would be to accept that both pro and anti migrants can be talking from a position of honest conviction and deep interests of their nations,people,world, migrants- all admirable affections in their own right.