The Holiday Inn - Manassas Battlefield is a nice property in a nice location, with a very friendly staff that smiles and tries to make your stay excellent. The hotel is very clean and convenient. That said, there are some things that need work.
First, as stated by a couple of other reviewers - there seems to be more than the average problem of loud guests and noise. I could hear pretty much everything in the hallway (despite being away from the elevator), and I turned the TV up so that I couldn't hear the adjacent room.
Second, water pressure and temperature was a problem. I was there three days; I tried showering at less "premium" times and still had an issue throughout the stay. I mentioned it to the desk, and on the third day the temperature was better with even less water pressure. Kudos to the staff for trying.
Third, the "free" breakfast buffet should be at least equal to what one might get at the Holiday Inn Express across I-66. There are significantly fewer selections, even though the items are the same foodservice bulk variety. The table service and televisions at each booth are a great touch, and again - the staff was quick, friendly and efficient. Management really should give them food commensurate with their desire to please the guests.
Overall, I consider this an average experience, which is a shame. With the staff and facility they have, this could easily be an outstanding property. It's a solid value in the highly competitive Dulles area, but if you are a light sleeper or rely on the hotel breakfast you might want to consider other properties.