Had a stay last weekend with one night in the Tysons corner property and one night at Pentagon. Both stays were in Executive Suites with a breakfast included package (Tysons gives a-la carte with a $60 limit for 2 people while Pentagon is buffet only).
Between the two, I'll give my vote to the Tysons Ritz as enjoyed the stay there more overall. The room was slightly bigger and felt more modern. Also the a-la carte breakfast was very nice as well while at Pentagon found the buffet to be lacking in variety (no pancakes, waffles, and just 1 hot dish besides potatoes and sausage/bacon). Of course the mall the Tysons is attached to is much nicer for upscale dining options compared to Pentagon.
Officially Tysons is classified as a 4 star property while Pentagon is a 5. I cant understand why given Tysons has a spa as well as a jacuzzi by the main pool both of which aren't in the Pentagon property.