Good Hotel
We stayed for 5 nights in September as we were attinding the Ryder Cup in Chicago. 
Our stay was very enjoyable with all services what you would expect from such a Hotel.
It is however a very business like hotel with what appeared to continually having many people in transit and with the reception on the first floor and no specific traditional hotel lounge area, this had the effect of taking any atmosphere away and making the hotel a little soulless.
The rooms were fine and the service was OK but my tip would be to avoid using the mini bar. (I know you expect to pay a premium in a hotel but Hyatts prices were ridiculous.)