If there's one scooter that would give the Honda ADV150 a run for its money, it's the Aprilia SR GT 200. Yes it also comes in a 125 cc version but it would make sense to bring the 200 cc version to the US.
If you could buy an ADV150 that is. ;)That scooter would run away from the ADV150. Limited dealer network in the USA would keep sales way below the ADV150.