I have friends who have been involved in an evangelical church plant in Ukraine. They had tried Russia for several years, but were harassed by the FSB and finally closed by them. They went to Kyev and have found it is a better situation. While there are obstacles set up by the various Ukrainian Orthodox churches, they can still practice their faith and evangelise.
I consider the Russian Orthodox Church to be a Christian church. If I were living in Russia for any reason, I would attend Orthodox services. I have more issues with the LDS and Catholic churches and several US protestant denominations than I would with the Orthodox church.