Stay at the Marriott City Center if you want to be very centrally located and get bonus points for priority status. However, the brand new Residence Inn is cleaner, cheaper, and offers free breakfast and dinner. The down side to the Residence Inn is that they only give 5X $$$ points whereas the Marriott City Center gives 10X + status bonuses.
I got the Marriott Charlotte City Center through Priceline for an upcoming stay; any comments on the hotel itself and parking? I'm going to be there on the weekend and I don't believe there's any game or anything then, so I would think parking would be easy and even free? Is on-street parking safe in the area? Does the Marriott have its own garage or just someone nearby?
There's a full service close to the airport called the Executive Park. Nothing too exciting around it, except for the Men's Club. There's another full service downtown. I've stayed at both of these and they are standard Marriotts. The TV's at the Executive Park are like 20 inchers...amusingly small for the huge space they allow. If I had my choice, I'd stay downtown. If it was just a quick trip, I'd stay by the airport.
There is also a Ren close to the airport but I've never stayed there.
There is a very nice Renaissance Suites next to the Coliseum. All rooms are very large suites. I actually prefer the Marriott City Center downtown, because they keep their indoor pool warmer :-). Just a quirky personal preference of mine. In my opinion the City Center Marriott is much better kept up than the Executive Park one. If I had a family with me I would choose the Renaissance because of size of rooms, otherwise I would go with City Center.