I stayed with my family over the recent Thanksgiving Day holiday. The Hyatt is situated right in the Reston Town Center which is a wonderfully built town with tons of great stores and restaurants with the traffic diverted to the outer streets of the town centr. Right outside the hotel was an ice rink and on the day after Thanksgiving the Town Center had a Thanksgiving Day parade. Rooms were decent size and quiet, but my biggest complaint was that the beds were Full's and not Queen beds. Supposedly they are upgrading to Queen's but for a hotel of this size and luxury the rooms should really have Queen beds. My suggestion to them is to get rid of the giant night stand tables - and just use one in the center and make the beds bigger.
Even though we were a family of 4 we did not get enough pillows nor towels and our toilet stopped up on the very first day. I did ask for extra pillows, towels and don't forget they will give you robes (only if you ask - be sure to ask for the Men's robes as they were much thicker and more luxurious than the women's robes-not sure why) and the staff was extremely accommodating.
There is a full gym and pool on-site - 3rd floor. We did not use the pool, but used the gym on several occasions and it was great - big, lot's of equipment, trainers on-site.
The hotel had wonderful holiday decorations with a great holiday train display...and they have a restaurant, a Panera Bread and gift shop attached to the lobby so there are things to do w/o leaving the hotel. The restaurant - Tavern was very good, but the staff were dim witted and our last meal there was almost ruined due to the incompetence of the waiter.
We have family in the area and would definitely consider staying at this hotel again.