When I first got into G scale I was already an o scaler. I had considered modeling American with G, but it made more sense to use G for strictly Euro modeling, as I already had a fair amount of American equipment in O.
That said, I started out all over the map with G scale, but now I try to focus on the RhB and the HSB, so I can run steam and electric.
So for me it's O scale for American prototypes, and G scale for Euro.
