Glad you had a good flight! Who knows who your neighbors would have been had the upgrade cleared.

I think a big concern is not only space but also cold and safety. Exit rows are safer. The safest place would be at the rear of the plane in an exit row. Oftentimes, though, it can get lousy cold on an exit row. So I am not sure if that would be my first choice (at least not a window seat) on a long flight.

Till