Depending on the country you immigrate in, there might be a language barrier, general mistrust and many other issues like finding a place to live (flat, house, etc.). Some qualifications differ, but of course in IT the definitions of roles is a bit vague, so it is less of an impact. Generally Russian IT people have the a stereotype going for them, to be very capable, at least where I am from. Losing friends and contacts is also something that will take time to build up again.