The Cat-4 Marriott properties that are close to IAD are the Washington Dulles Marriott and the Washington Dulles Marriott Suites. The Washington Dulles Marriott is very old and the rooms are small, particulary the bathrooms, but it does have a nice lounge. There is usually a managers reception on Tuesday nights with free beer and wine. The Washington Dulles Marriott Suites does have nicer rooms, but there is no lounge and no weekend breakfast for elites. The breakfast buffet during the week is adequate, but not too exciting.

The Cat-4 properties close to DCA are mostly Courtyards and Residence Inns. I have not stayed at any of these properties, but have at some of the Cat-5 Marriotts in the area.

Your choices are pretty limited to the Dulles Marriot or Suites, if you want a full service Cat-4. If you will be there during the week, I would go for the Marriott Dulles if you want lounge access or the Suites if you don't care and prefer a nicer and larger room. One of the nicest Marriot properties is the Residence Inn at 28 Center not far from the airport. This is a very upscale Residence Inn with nicely furnished rooms and a large lobby with vaulted ceilings and chandeliers. Not like most Residence Inns that I have been to. The breakfast and dinner options are not too bad and there is free beer and wine during the week (Mon-Thurs). This property is only a Cat-3.