That looks really cool. Which of the 2 areas would you prefer? Haven't been to DC in 20 years.
It depends what you are looking for. National Harbor is shiny and new with modern amenities such as an MGM Grand hotel and casino, a London-esque Ferris wheel, medium and high-end chain eateries, a big resort, outlets, etc... Old Town(e) is 350 years old, replete with centuries old brick buildings, brick sidewalks, cobblestone streets, all modernized into nice restaurants, boutique B&B's and historical restorations of the revolutionary and civil war periods. So, it's a personal preference thing and you can't go wrong either way.