The Euro has lost 80% of its purchasing power since inception when compared to a stable currency like gold -
http://www.marketoracle.co.uk/Article30920.html
Marginally better than the other flawed fiat papers but not much.
Comparing one independent variable flawed currency verses another independent flawed currency is not a valid method of determining the strength of a currency, particularly as a future global reserve currency.
The euro has maintained a relative 'strength' against the other flawed paper due to the reluctance of the ECB to bring in QE and the reluctance to cut rates as much. If the Euro is to survive then the ECB will have to open the floodgates to printing further in order to pay back in a ponzi manner the unsustainable levels of debt.
The Euro may play a role in a future basket of currencies but it won't be a major player.
No nation or group of nations with rising unsustainable debt levels approaching 100% official GDP and 300% unofficial will last long as a global reserve. The euro zones debt is rising year by year. Until the deficits turn into surpluses, the fiscal position of the eurozone is getting worse, not better.
Deficits of 5-10% and growth of only 1-2% per annum and starting 'official' debt of between 60-150% of GDP is not the basis for stability, the prerequiste for the global reserve currency. The UK had stability in the 19th century and lost it, together with the global reserve status of the pound. The USA had economic stability in the early half of the 20th century and then lost it. It is only a matter time before the dollar is replaced by something more stable.
Gold, silver, platinum, Yuan, etc are the prefered stable alternatives. Doubt it will happen quickly with the reluctance of the USA to start being productive instead of relying on Asia to do their productive work for them.
Perhaps a future war over rising debt and commodities will be the instigator for the change.
UK 19th century, USA 20th century. The 21st century's global reserve currency will belong to the next global power.
Hopefully the world will agree to put in place a stable and truely global currency (ie gold) instead but I wouldn't bet on it.