Well, you still have to change terminals at ORD, but it's a much more distinguished set of buildings, for what it's worth. I love the United terminal at ORD, it's more than 20 years old but has aged very well, despite all the changes to air travel since 1987.

IAD, on the other hand, for a major point of entry to the U.S., is ugly, and has the ambience of a trailer park. If only they can make the satellite concourses as magnificent as the main terminal.

As for luggage misconnects, I haven't had a problem at either, and arguably, connecting at IAD is not all that inconvenient. It just looks and feels terrible.