I commute to work on mine and frequently do 70 miles on motorways to my girlfriend's house.
I find myself far less tired getting off the SD than I have any of my previous bikes, the riding position is perfect for me. The wind blast does start to get a bit much over 100mph, but lean into it and it's fine again. Besides, the speed limit over here is 70mph anyway and over 100 means an instant driving ban!
I'm 6'6", so if I don't find the windblast too much I doubt many people will.
As for riding in town and in traffic it is just as much fun, if not more, specially if you put the Akra Evos on it, they sound phenominal and the popping on the overrun is enough to make you fall in love! Also the looks you get from everyone in town on such a fantastic machine make the entire experience very enjoyable!
I have ridden two up with my brother, who is a skinny thing but measures in at 6' 4", he was perfectly happy on the back of it for a couple of hours, as was my girlfriend, but she's tiny so doesn't really count!
I'm taking the bike touring for a few days in France this May and am looking forward to every second of it.....it might not look like a tourer but it's much more comfortable than any sports tourer I have ridden thanks to those lovely flat wide bars and the fairly upright seating position.....(when you have monkey arms like me).
I had the Adcenture as a courtesy bike and compared to the SD if felt like riding a tractor. Change your bike, you won't be sorry, I promise you that!