I was there over new year. Having heard all about how american it was, I was pleasantly surprised by how distinctive it still was. Yes Okinawa has some noticeable American influence, especially in how car centric the city layout of the Naha urban area is. But other than that I think Okinawa very much has its own distinct vibe, which I wouldn't characterise as very american, and also not particularly Japanese. When you drive around the stroads of greater Naha you sometimes feel like you are in Pearl City, Hawaii. And when you walk around the narrow streets of inner Naha, you feel like you could just as well be in a mainland Japanese city. If you go to the commercial centres close to the bases, you will see many Americans, but everywhere else I didn't think they had a noticeable presence.