The entire team at the Hyatt Regency Dulles was welcoming. If I had a question or need, they helped.
The lobby area had a private events area, a bistro and bar, and of course the front desk. Also on the Lobby level was the gym and pool area. The gym was pretty decently equipped, the pool was a lap pool, and also in the pool areal was a jacuzzi. All of the areas were spotless.
Our room was quite spacious for the price point. It was well laid out and very clean. There was a microwave, small fridge and small table for the kitchen, a couch with a coffee table and end table.
The bed was queen size and the bathroom had a standup shower, vanity with washbowl, and toilet. The only real "closet" was in this area.
As for the negatives, there was only one, and it wasn't a big deal, although it appears to be for some. The elevators there are in need of some tender loving care. The inside is spotless, like the hotel. It's operation is a wee bit sketchy, with some noises and sometimes inconsistent operation.
If you don't want to each at the bistro, just know that there doesn't appear to be anything in walking distance of the hotel. On average, the closest places were about 5 minutes away.
All in all, a great visit and will absolutely stay there again if the need arises.