Usual expectation for a JW - Great location
The JW Marriott is located very close to the White House and the National Mall area so it's easy to get around. The hotel was very nice and is constantly busy with conferences and other political related events.
All the services and rooms were as expected for a JW brand. Nothing really stood out to me as a "wow" factor other than the location. I was on the concierge floor and from the concierge lounge, the Washington Monument is like...right there! 
We did not try the room service or restaurants as there are many other places around town that we wanted to try. Overall I enjoyed the 4-day stay and would recommend to others as well.