I got a better room than the Hyatt forum moderator.
Still, it was all very odd. I spent 15 minutes on the phone with 1-800-CHECKIN, as they conferred back and forth with the hotel and me. Eventually, I was assigned 804. When I got to the hotel, I was told I was upgraded - to 908. You can imagine how I reacted to getting one of the dreaded xx08 rooms! I couldn't extract any explanation as to how they could give away the room into which I had been checked.
Ultimately, since I refused to accept 908 (despite the desk clerk assuring me it was a lovely room and one in which he personally liked to stay) I was given a wonderful rom, xx06 - looking straight at the Water Tower and beyond to the lake.
I am bemused about the room problem. Never once did the desk clerk explain or apologize.