I'm going to DC in october, flying from BDL. There are many nonstop flights per day to IAD on UA and to DCA on US.

I have the UA economy plus yearly pass, so i can get better seats on UA, but will be spending the entire trip in downtown DC, so it seems DCA is much closer (I've never actually flown into DCA).

Ticket prices are the same in principle, but I do have a $75 voucher I can use on UA which will drop the price down. I'm unsure if having to get to and from IAD is a worthwhile price to pay in exchange for $75 cheaper ticket and an E+ seat. what are people's thoughts?

how much does it cost for some of the options for getting downtown from IAD? I assume from DCA i can just take the metro to my hotel.