Nice, but not impressed, especially for a Hilton.
First off, I am writing this review based from the opinion as a Hilton Diamond member. I will say that the room rate was pretty low in comparison to local Hilton properties, but at the same time, I got alot less for my money. My room was pretty small, and the bathroom was smaller, to the point that the sink literaly starts to extend over the tub. The hotel does offer snacks and breakfast to Diamond members on their 10th floor. The snacks are snacks, but when i stayed, the room was completely crowded, and it was the first time I have seen packs of children in an executive lounge. The breakfast selection was limited, with no proteins except hard boiled eggs I believe. Again, it was packed. There were 8 people in front of me trying to get a cup of coffee, and I retreated to my room to make a cup there, and avoid all the crazyness. 
If you are in the area to see the sights, then the location is great for this facility. If desire space, and the full Diamond treatment, I would not recommend this hotel. You will encounter DC traffic if driving, so add an additional 30-45 minutes to get to and from this hotel. Be ready to pay $34 to park your car, per night also. I had to go get a print off of my receipt, due to the hotel being paperless. Good luck getting out of the parking garage, my keys failed to work, and I had to show my receipt to the attendant to show I had paid for parking, then sign something, to get out. Maybe it was just a fluke, but still, it was frustrating, and time consuming.