Compared to the Chicago el, which I take Mon-Fri to the loop, the DC Metro is amazingly clean. I am in DC about 5 times a year on business and usually take the metro- but I am in DC proper or occasionally Arlington, so it's a different ball game coming in from the suburbs. Last year I took my elderly mother who will not use escalators- she has a fear of the them and we ended up having to use cabs- trying to find the elevator at street level was sometimes very difficult and far out of our way in the larger stations and it was just too much walking.