In the early 90s I was on a week long riding trip and ran into a German rider at Deal's Gap who had shipped his F650 Funduro to the USA to do some riding. I asked him why he was riding over here when there were so many great roads in the Alps. His reply was that there was much less traffic over here. I'm not sure that is true any more since Deal's Gap is practically a traffic jam on weekends these days. Back then it wasn't.
This was before the F650 had been released in the US. We swapped bikes for a bit and I got to ride the F650 before it was released here.
I have never ridden in Europe although I have driven a cage there. Riding in Europe is on my bucket list.