Just came back from a holiday weekend in DC and stayed at the Grand Hyatt. First off, they offer some great weekend special rates via their website. For those looking for a decent hotel with a prime location at a great rate, this is where you should start. That being said, my review is based on a stay with a highly discounted rate on a holiday weekend.
The pro's are many. This is a standard, large, convention-type hotel. The property has a lovely and open lobby that gives it a pseudo resort feel. The staff at check in were pleasant and efficient. The room was a standard Queen on the third floor. Quite spacious with a couch, nice sized closet, LCD tv, minibar and roomy bathroom. The minibar is locked, so if you wish to have access to the minibar, you need to contact the Front Desk and they'll send someone up with the key.
There are 3 restaurants on property. 1) CURE (bisto and wine bar) which we found trendy and had an interesting and varied menu. This place was perfect for a nightcap. 2)Grand Slam Sports bar (the name says it all). 3) The Grand Cafe - has a great buffet breakfast. You also have the option for room service until 1:00am.
We spent most of the day touring the city, so I can't comment on the gym, pool or business center- sorry.
Parking is underground with an elevator directly into the property. It can either be valet (extra charge) or self. The daily rate is $30.00. Pricey, but equal to the other hotel locations in the area.
Location is the big plus. 5-10 minute walk to the White House, Washington Monument and the Mall. There are other hotels nearby as well, but they were much more expensive. Keep in mind, like NYC, you pay for location primarily. But I must say we had a good experience here which is a bonus.
Cons are few. If you paid a high rate (say over $250/nt) then there would be reason to complain. Details like housekeeping visits at 9:00am, once even opened the door without knocking (obviously in error). Room had no desk and chair for business purposes. I don't know if the other rooms had them, ours didn't. Just to be picky, a smaller detail like water glasses in the bathroom (they had them on the bar, were they multi purpose?) could pose a problem if you don't want your Scotch to taste like toothpaste.
All things considered, we enjoyed ourselves here, the staff was very friendly and location couldn't be better. We would come back.

Myself, my husband, mother-in-law and teenaged son booked 2 adjoining rooms for Labor Day weekend 2010. The hotel itself is simply beautiful; with its atrium design; water features; terrific restaurants and central location. The on-site Starbucks is perfect for grabbing a coffee and pastry, then getting out the door to wherever you're headed!
The rooms themselves are very tastefully appointed and chic; we slept soundly and thoroughly enjoyed the large flat screen TV.
The front end staff were so friendly and efficient! (especially Rebecca W. and Joe H.)
We have a habit of trying different hotels in any city we stay; however, we've now decided that the Grand Hyatt is THE hotel we will stay in anytime we're in DC!

Got a last minute deal on Priceline, which is likely why I am extra enthusiastic about this hotel! But really... beautiful atrium lobby with waterfall and the welcoming staff sets the mood for the start of your vacation. The check in was first rate. The hostess accommodated my need to have adjoining rooms, after doing quite a bit of detective work on the reservation system, and some rearranging on her part. I did have to wait for the rooms to get cleaned, but didn't mind. I left all the luggage with the bellhop which was taken to a secure room, and we were able to enjoy the afternoon while they prepared our rooms. Excellent service Janeel!

I was at the Grand Hyatt for an annual conference. I was impressed by the staff, starting with an email from their VIP Manager before my stay. I had requested a refrigerator, and it was in my room upon arrival. The catering for the conference was impressive - there were hundreds of us and the meals - from the gala reception with more than a dozen overflowing food stations that ranged from pasta to sushi to crab cakes to short ribs and more to the plated and buffet lunches - were both plentiful and delicious.

The staff was very attentive and the room was very comfortable. The bathroom was luxurious and I slept well each night. Internet and parking were both pricey, as expected at a full-service business-oriented hotel. Since my company was paying, these were not as painful as they would have been coming out of my own pocket!

Although I barely set foot outside, the hotel is in a perfect location, convenient to the metro and to some of DC's most sparkling sights.