Well, crime statistics from many European countries, show them as being overrepresented. It is interesting that none of the people here seem to be able to answer the simple question of why Sweden for example stopped collecting evidence regarding the nationality of perpetrators.@ioannis: You're again mixing in dubitable assumptions and generalisations, for example that muslims in general are prone to crime. How are we supposed to reach a fruitful conclusion when you keep heaping suppositions on top of each other?
The benefits of a multicultural society are yet to be revealed to me. With the exception of food (I am from Greece, we have excellent food on our own), and "genetics" I haven't seen much in the way of the benefits of "open borders". On the other hand, acts of terrorism.
I believe that you suffer from "white guilt", something that does not apply to me, since far from having slaves from Asia or Africa, my nation was itself attacked by asians (in antiquity) and enslaved to other asians much later. I would advise you, though to get rid of this "white guilt", because some people will use it against you.