Big hotel, great location.
My husband and I stayed one night at the Washington Hilton in Washington D.C. Check-in was a little slow-going and the price of parking is outrageous (which is normal for D.C.). I asked for a room on a higher floor, but out of 10 floors, we were placed on the 4th floor. So, that being said, this hotel does not seem to honor requests (I had even called ahead and placed my request in advance).
Our room was very small, but the use of space was efficient and it was clean. Our view was fantastic, even from the 4th floor, so that was nice. Our King bed was extremely comfortable and we slept fairly well, but could hear our neighbors next door early the next morning. Also - housekeeping knocked on our door at 8:30am, then again at 10:15am. Both times I said we would be checking out at 11am, so I'm unsure as to why they kept coming back to our room over and over? It was annoying.
The location of this hotel is very good. We were in walking distance to Georgetown (about a mile away), Dupont Circle (the Dupont Circle Metro is about 4 blocks away), Adams Morgan, and the National Zoo. The hotel is surrounded by restaurants and nice shopping. 
Staff at the hotel was friendly and the lobby area is a combination of a lounge/coffee shop/and Wifi area. It was very busy and there were lots of people around. One downside to this place is that you have to pay for wireless in your room. I can't remember the exact price but it was somewhere between $9.99 and 12.99. That's kind of a rip off considering you've already paid for your room, an extra 30-something dollars for parking, PLUS Wifi charges? Yikes! Oh, and there is no mini-fridge in the room, so prepare yourself to grab a bunch of ice.
Overall, nice stay but we may not stay here again due to all the extra charges added onto our final bill. If you want a good location in a super big hotel with all the bells and whistles - this is the place for you. We will probably downsize next time and stay in a more quaint hotel.