I'm amazed that nobody seems to have mentioned money yet. In the west this is clearly not the case (here I think some people simply become Protestant for an easy life - little or no ascesis, an assurance of salvation, etc.) but I'm familiar with an awful lot of Pentecostals in Romania and many of them converted in order to get their hands on western aid. They are generally not ex-Orthodox (except nominally) but rather ex-communists, though I have no doubt that there are ex-Orthodox there too. Interestingly, I've seen little to no evidence of the sort of easy life, feel good Protestant groups doing well in rural Bucovina. The Pentecostals, who get the lion's share of all converts to western churches in the region are particularly strict. I have no idea which church they are actually a part of but to give you some idea, they don't drink or smoke, the women always have their hair covered, never have shorter than knee length skirts, they have huge families as they frown seriously on contraception. I wonder if there is something of Orthodox ascesis imprinted on these people even after so long under the communists, such that a religion that really requires nothing of you seems like no religion at all? I've certainly yet to come across a single mainstream Protestant out there.
Just to be clear and so as not to give the wrong impression, I know many of the Pentecostals there because I was working for a Protestant charity when I discovered Orthodoxy - they are actually a pretty tiny, though very visible, minority. There are, however, a few villages where 'economic evangelisation' has made them a majority. Nonetheless, all the Penetecostals in town fit comfortably in their rather modest church on a Sunday whereas it's almost impossible to get into either of the two Orthodox churches even on weekdays and the Roman Catholic and Greek Catholic churches are pretty packed also. I'd hate people to get the impression that Protestant evangelists are winning in the east. Far more are returning to the faith of their forefathers than are leaving.