Ukraine to Russia immigration is negligible. Not sure if it's even bigger than Russia to Ukraine immigration. But if you're referring to Ukrainians seeking jobs in Russia, then of course it's quite different- things people put up with for a buck. (Actually look at me- I travelled half way around the world for that too.)
Over 20% of the contract military in Russia is Ukrainian. I got to see that first hand in Bosnia and the contracted airborne brigade there. Ukrainian workers are all over Russian construction sites...don't try to make crap up. Maybe in Western Ukraine its true, its a pure lie in Eastern Ukraine but then again, the nationalists don't consider anyone in eastern Ukraine "true" Ukrainian anyways.