This paper might be helpful, as it weighs in on the simpler question of 'should they join' -
Frankel, Jeffrey, 2008. "Should Eastern European Countries Join the Euro? A Review and Update of Trade Estimates and Consideration of Endogenous OCA Criteria," Working Paper Series rwp08-059, Harvard University, John F. Kennedy School of Government.
Thanks. Well I'm a bit confused, as the way I see it, there are 11 countries which have joined the EU but which have not adopted the euro, but by agreeing to join the EU, they have committed to adopting the euro, providing their interest rates fall within certain perameters. Only UK, Denmark and Sweden have opt-outs or have found legal loopholes. I don't see how I can debate whether they should adopt the euro, when evidently they already have. Or maybe I'm over-thinking things?