The great debate!
I know the problem! Still, remember this is a great problem to have -what bike to buy for my world trip! ( I see now you intend to travel the globe, not just the U.S ). However, if you find both bikes comfortable, then I guess ( as the previous writer adds )an important aspect is how much servicing you can handle yourself. If you plan to visit dealers en route, then it really does not matter - both bikes should be fine, BMW better built and excellent dealer service.
If you want to become even more confused, can I suggest a ride on the Honda Transalp ( XL650V) ? A bit like both of these bikes in one......tried and trusted engine, low state of tune ( normally very, very reliable), easy to service, albeit a bit fiddly.
Let us know how you get on with this decision!