This Hilton is going down the tubes
Hilton is a strange, inconsistent hotel brand. In 30 years of international travel, I have stayed in Hiltons that deserve five stars, and I've stayed in Hiltons that don't even deserve three. The Washington Hilton is closer to the latter. Granted, it recently had a renovation to the rooms, and they are up to a good standard. But despite the renovation, all is not well with other parts of this hotel, and I think part of the problem is the management.
Today was a total mess. A dance event called the DC Bachata Congress and International Latin Dance Festival totally overran the property. It looks like it runs for four days. There was a very loud, huge dance party on the main lawn, with a DJ shrilly yelling over the music. If you were not there for this dance party and had, for example, small children or simply did not want salsa music thumping in your room, say while you are trying to finish an important report while traveling on business, you were out of luck. So my guess is business travelers and families were not pleased with the failure of management to keep this event from encroaching on their peace and quiet. Heck, I'm surprised people in the neighborhood weren't complaining. You could hear the dance party over a block away.
You were also definitely out of luck if wanted to enjoy the pool. It was packed beyond the point of over-crowding. The water was dirty, or to be charitable, not clean. I went there hoping to get a swim in, but the single swim lane had been totally over-run. The life guards appeared to have given up on trying to control this crowd. I felt sorry for them. It was not their fault; it's the fault of whoever manages this property. One old lady tried to swim but was totally overwhelmed, but people jumping into the swim lane and couples just hanging out in it. There was not a single lounge chair to sit on, not to mention hardly any space in the pool. In 30 years of international travel, I have never seen such a mess at a pool in what should be a five-star hotel. It looked more like a motel at Fort Lauderdale during spring break, than a Hilton. 
And coming back to the renovation, while parts of it brought the property up to 2012, for some reason Hilton left other parts of the hotel as is. One of the bars looks like it is stuck in the 70's, which when it was probably last renovated. It went with that fake English pub look that has not been cool for a very long time and stands in stunning contrast to another bar just down the hall that has a modern theme with clean lines and stainless features. It's also too bad that the renovation did not do a better job of capturing the fact that this property is architecturally very interesting as a modernist structure. The result is visual cacophony, which I guess fits with the musical cacophony blaring out on the main lawn.
There are plenty of better hotels in Dupont Circle. Give this place a pass.