I had a great stay at the Black Swan. Everything was great. The kitchen is a bit sparse on cookware, but it was fine for me making dinner every night. Oh, and local Small Planes coffee was a nice touch.
It's a very nice space in a great neighborhood. I was there for work and walked to the convention center every day. There's a Whole Foods nearby and a short run will get you to the Potomac. I will stay here again the next time I'm in DC.