Also just stayed last week on a Diamond Suite Upgrade. I never have service problems with the hotel at all--no line at check in or out. Got a large suite 1412. Suites are actually quite nice--not as dated as the rooms (except still the tube tvs), and two bathrooms. The full bath is as small as the baths in the regular rooms, and the typical amenities plus qtips and such. The room was in excellent condition and clean.
As part of my new year's resolution, I used the workout facilities for the first time. Great workout area and equipment. I was impressed. The only issue is having to walk past the front desk and through the convention area to get there.
Breakfast is average--buffet has a few of the typical things, but eating here really really blow me away. I used the coffee shop for my Diamond breakfast one day.
Dinner was at Bravo and Big Fish a short drive/walk through mall parking lot. Good choices, along with a PF Changs next to Bravo. I've got 2 more stays here in February. Wish it had more amenities, but it works, and I understand it probably struggles quite a bit with the Detroit economic situation and being such a huge hotel.