If you were a marshal of army, you would probably seek to attack when the opponent is weak. Similarly, when it goes about international business, you need to choice right time for your intervention to another country.
In despite of economic boom in Ukraine during 2004-2008, the vast majority of markets are still far from saturation. The competition is much more fragmented comparing with countries to the West. Many local players, dependant on lending, were knocked out by economic turmoil. Management culture as well as service level in Ukraine do not meet European standards. Thus, foreign firms with midterm and longterm strategies can take advantage by positioning themselves in Ukraine these days.