I understand that Hungary and Czech are not in the Eurozone (it does not seem like they are willing to join in the future too, after seeing the PIIGS crisis unfold before their eyes). But all larger EU-CEE countries had their own currency, had they not? I think that the good times when everyone wanted to be a part of ERM and join the currency union certainly are over.
As for the cost of living, you should realize that with the customs union, the difference in price of consumable goods is, shall we say, not an order of magnitude, and the savings that a person with a low monthly income can make is likewise limited. The cost of living differences are manifested in lower rent and public services prices (train, bus, etc.).
An illustration of this stall in convergence:
EU-9 convergence is flat, for some it is actually worsening. Finally, there is this chart, which shows that convergence indeed has slowed down dramatically even for Central and Eastern Europe countries due to the crisis. They are still converging, at least, but this slow convergence is hardly some ground to celebrate, as the same period is marked by massive Southern Europe divergence: