Westin Tyson's Corner
Finishing up a stay here now. Got an excellent weekend rate of 89 per night.
As gold, I received a room on the 10th Floor (Starwood Preferred Guest Floor) facing the road, and it does indeed suffer from road noise--but I was too lazy to request a room on the other side. Pulling baqck the shades eliminates a decent amount of it. Room amenities include free bottled water, in-room coffee as noted previously, and there is indeed a mini-bar in the room, so they seem to have fixed that problem. Decor and ambience is Westin-like, but I wouldn't say this place is truly full service. There is no convenience store on site, and dining options are limited. Did not try the room service. During my stay, the ice machine was broken, and I had to go to another floor to get ice.
Parking is ample and free for self parking, or you can choose valet for a reasonable daily or overnight fee.
Elevators are a bit cramped still need re-furbishing, but I'm sure it's not a priority.
I've stayed at Sheraton Tyson's Corner as well, and it is a little nicer and has more services than the Westin. However, the ambience here at the Westin is friendlier and staff are more attentive. Would stay at whichever had a better rate.