Back when I lived in the area, 15 years ago, I preferred Dulles airport-- I was 15, so I wasn't take a lot of flights on my own, but Dulles was the nearby airport that had a name, while Reagan National was, at the time, merely boring ol' National Airport. I didn't even know about BWI at the time.
Dulles' main terminal is, IMO, spectacular; it's like waiting in line under an impossibly large blimp. I always though the mobile lounges were novel if dated, but at least they had a decent system so you weren't waiting for long or crowded in, in my experience.