Strong vote for DME. There is an express train that gets you into central Moscow, so it is as quick or quicker than the train-metro combo from SVO. DME is vastly superior in facilities, the most important to me being the immigration counters. At SVO, you can get stuck in the unbelievable chaos of immigration for an hour-plus. If you're not seriously aggressive about cutting in front of everyone possible (because they're doing it to you at the same time), it can be longer.

I arrived at DME on Monday night and was through immigration, via standing in an orderly line, in five minutes. I have been traveling to Russia since 1988 and that is my best time ever. Granted, flights to Russia are going 2/3 empty these days because of the economic downturn, but it was still incredible. I left via SVO this morning and waited about twice that length of time to go through immigration on the way out.