When it comes to convenience, there is no comparison. As for safety, you are quite correct that it is more dangerous, statistically speaking, to drive to Dulles than to land at National (excuse me, Ronald Reagan Washington National)...But during my tenure working on Capitol Hill, I had ocassion to tour the FAA facilities at National, and heard the ATCs there tell me (as a Congressional aide off the record) that each and every day there is a "near-incident" involving a landing or takeoff. And that's at the airport...never mind the twisty, turny approach or the noise restrictions requiring low throttle take-offs. Also, if (when) the 30 year old ATC system fails, National will be scene to a trajedy if a plane is on approach from the north on a cloudy day.

I DO use RRWNA from time to time (that's how I know about the whiplash), but not if I can help it.