I have only stayed in one - the CY at DCA. I stayed in it when it was about 3 months old - thought it was a very nice Courtyard. You have access to Metro nearby, plus a bunch of restaurants/shopping within walking distance.

I suspect that this property is the nicest of the three Courtyards, as I seem to recall it being "near full service" (e.g., full late-evening bar/restaurant), whereas my hunch is that the other two are more typical CY's with breakfast service only. (But I could be completely wrong...)

I think you can safely rule out the Fairfield unless you strongly prefer its location. No idea about the Residence Inn...those properties range from very nice to very worn out.