I have only flown IAD-LHR on UA, and the service in C has always been stellar. The crews have always been IAD based. A few of the female attendants have been perhaps a little bit too friendly at times - but hey, this is the friendly skies, after all! I have been flying this route since the Pan Am 106/107 days in the late 1960s and have had seatmates that date themselves back then, too! I have always requested - and received - a window in the mini C cabin on the tripple 7 (I understand the 767 has the new C seating but its schedule is less convenient for now) and the service is great.