This was my first time in National Harbor (and sadly, it was work-related), and this is one of several hotels in the area. Overall, it's quite nice, only charges $13/day for parking, and the staff is great. The pool was closed for maintenance during my entire week's stay, but the manager sent me an email before I even arrived to inform and apologize for the inconvenience, which I actually thought was quite professional.
The only real downside is that the Gaylord was right across the street, and looks AMAZING. If I ever come back on my own dime, I'll probably have to check it out.