Regarding Prosecco, Cava and it must be mentioned Crémant de Bourgogne, it is usually best to drink whatever is local, the US being the exception to that rule. So when in Spain I drink Cava, in Italy I drink Prosecco or if in Asti of course I drink Spumante.

And here in Burgundy we drink Crémant de Bourgogne much more than Champagne. It's much cheaper and just as good as all but the very high end Champagnes. Also, it is a little known fact that most of the grapes used in the top Champagnes actually come from Burgundy. However Crémant de Bourgogne isn't exported much, except to Holland for some reason. You won't easily find it in the US.

I was in Strasbourg recently and picked up a box of Crémant de Alsace. It's ok, but it tastes quite different as you would expect. I'm not a fan. But some very good Gewürztraminer can be found in Alsace as well as Pinot Gris.