I am a regular traveler in the Midwest and for years have had top status in three chains, including Marriott and Hilton. The treatment I get with status, or for that matter, without status, is far more dependent on the individual hotel than on the brand. Unlike most FT posters, I do not value a suite unless the wife is with me. I do value getting rooms that are clean and quiet. It is amazing how often I am treated to rooms overlooking an all night biker bar next door, rooms on the freeway side of the hotel, rooms with adjacent room doors (always noisy), rooms near ice machines or the elevator, rooms with elephant walkers above (I always ask for top floor, but often do not get it). If I owned a hotel, I would know which were the best rooms (noise especially), and would instruct whoever is assigning rooms to make sure they take care of the top elites. It appears to me that room assignment is basically random and is usually done without regard to room quality or guest status.
Like the posters above, I am not single hotel brand loyal, simply because not all brands are represented everywhere. I do consider value. I do include the room price, parking cost, internet, and breakfast in the price comparison of alternatives.
If I have a general favorite, it is HGI. Almost always a winner if I have a choice, unless it is poorly located or very high priced.