From NR:
“Greece’s main problem is that its currency overvaluation within the euro is on the order of 30 percent or more. Any new government — however successful at restoring the nation’s public finances — cannot possibly improve the productivity of Greek workers by one-third in any space of time. The more the EU softens the terms of its assistance, moreover, the less incentive Athens will have for trying. And the harder it tries, the more likely it is to provoke social unrest, to strengthen Syriza, and to weaken the commitment of the main center-left party, Pasok, to its governing partners and the deal with the EU.
Staying in Euro is a trap for the Greeks.
That is an apt observation. I can't disagree with it. But Greece will either go through a self-imposed devaluation by adopting its own currency or it will suffer another type of devaluation [deflation, actually] by staying in the Euro. Greece has no easy way out.
I tend toward the Euro because the politicians in Greece have no, or not much, control over it. By leaving the Eurozone, they will undoubtedly take the savings of the Greek people to make the government's balance sheet look better. In the Euro, they have no choice but to cut spending.