I fly through IAD whenever it is an option.

Negatives:
-having to bus to the outer gate areas;
-no easy public transit access;
-potentially very long security lines;
-construction/crowded main terminal;
-prone to weather delays in the winter.

Pros:
-Normally very efficient (and thorough) security;
-Quick baggage handling;
-No hiking for hours as in other international airports on the East Coast;
-Curb-side check-in works well;
-Good layout for picking up passengers on the curb (easy to circle while waiting);
-God-awful smoking lounges (can be a negative, but vital during long delays).

I detest the New York area airports, I'm afraid. Philly is just too big. ORD is out of the way for me, as is Atlanta. Charlotte is nice, but only useful for US. I fly back and forth from FRA to IAD regularly, and rarely have issues of any sort at either end. The problem with DCA is it's only domestic, so I'd have to connect to get there. I like DCA and tend to use it for my domestic travel primarily because the Metro goes there. BWI is a good airport too if you live in the North DC suburbs or anywhere else in MD.

The primary thing for IAD is plan to get there earlier than usual. 2.5-3 hours is my normal target. I always (9 out of 10 times) breeze through and end up sitting around for 1.5 hours after security/the bus. Vastly preferable to being late, though. I also try to fly at odd hours to avoid rush hour, but that's a personal preference. Most of my travelling companions try to kill me when I book the 0600 departure.