we stayed for 3 nights as part of our move to the DC area.
some positives are:
1) excellent staff - the valet couldn't have been any more helpful with helping fetch porters for the 10 or so bags that we had with us (funny how all those things you didn't pack add up), and the porter was very gentle with our stuff. he spotted luggage that had been damaged by the airline which we hadn't noticed and made sure to remind us to claim it right away (yet more damage by a double A rated airline that gets an F for baggage handling and customer service). the front desk people were very pleasant and efficient.
2) spacious room (for all 10 bags), plus a small fridge in the room. nice beds. plus, you can get exercise gear for a one time $5 fee for the duration of your stay. and the sneakers were in new condition - i was half expecting them to look like "bowling alley" shoes.
3)westin alexandria = endless hot water + plush bathrobes + quiet rooms = great after a hard day
things to watch out for:
1) no coffee in the lobby. yes, there is the de riguer coffee maker in the room, but its not the same. there is a starbucks just around the corner. no big deal when its nice and sunny. not so great when you have to go outside in the early morning on a cold, blustery and rainy day to get coffee.
2) there is only one restaurant. it would be ok if not for the fact that someone booked a private party occupying more than half the place and being extremely loud as well. hard to eat if you can't sit, even a the bar.
3) no restaurants or bars in the immediate vicinity. yes, there are a couple several blocks away. it would not be a big deal when its nice and sunny and warm. but in cold, blustery conditions late at night, its not a great. there is a shuttle bus, but those things are never around when you want to go out for a quick bite and a drink. (by the way, there are several shuttered / closed restaurants around this westin, so its probably not for lack of trying).