It depends on where you're getting on and how many transfers you've got to deal with.
A lot of places on the red line are just awful getting on each morning. Really, you've got to either wait several trains, or if you're not bashful, just shove your way into the sardine can.
Then there's the breakdowns. Metro doesn't have any express lines, so when there's a problem on one track, it screws up the whole line. It'll happen every once in a while and cause a mess.
I guess it really depends on what type of person you are, not to mention what type of car you have.
Some people would just MUCH rather be in their own car, in their own personal space, listening to their music, with their coffee and their bagel (and their cigarettes if that's their thing), doing their commute. And if it's bumper to bumper, they'll just sort of deal with it if it means avoiding being crammed on a train.
Others would rather walk to the metro, go underground, take their seat and just read or zone out for a while until it's time to work.
You just have to go with your gut I guess.