Living on the Border of a Currency Union

Countries joining the European Union after the establishment of Economic and Monetary Union and passing of the Maastricht Treaty could have no say on the design and rules of the Euro zone. They could only enter the zone as it existed, or postpone entry, perhaps in fact indefinitely. The European Far North, member countries north of Germany and around the Baltic Sea, offers a fascinating natural experiment: why did very similar countries come up with a wide variety of solutions? Further, did the institutional choice have an evident impact on the relative economic performance of the countries?