Very Nice Conference Hotel
I was at the Detroit Marriott for several days during a conference in early 2008. The conference rate for the rooms was not at all expensive, and the rooms were quite nice. My room on the 21st floor had a great view of the river and the bridge leading into Windsor, Canada. The beds were very comfortable, and the room was clean and well appointed. Even though the room had floor to ceiling windows and it was 3 degrees outside one night, the room was cozy and warm. There was plenty of (relatively affordable) parking, the dining options were good in general, and the restaurant on the 74th floor was really very nice, although not inexpensive!
The mall and food court attached to the hotel is a nice touch, although many of the shoppes seemed to be closed, or have limited hours. Other restaurant and shopping options were nearby, however, and the hotel is within a couple of blocks of the annual "Winter Blast" venue.
I really enjoyed this hotel, and would recommend it as a competitively priced option in the downtown area.