There actually was already a thread where we had some feedback on the Euros in Istanbul.
Don't really know how countries with two teams did it, as they didn't really gave feedback so far.

Will there be another clash in two years? Personally I fear there will be. Our lovely sport has split up and in the end it will be very very difficult to keep playing both sides as a country. At some point one of the two governing bodies will demand exclusivity, which will force federations into taking sides.
We all know it is completely rediculous and mainly based upon personality clashes, but that's just the way it will be.