We arrived at the Omni on 2nd September for a 6 day stay. I took ill when I left the plane after travelling from Manchester so I saw more of the room than I anticipated. I couldn't go out for 4 days. The room was spacious and clean. The bed was extremely comfortable. The bathroom was large and very clean. What more could you ask. We had coffee and juice left outside our door every morning at the time we requested. I managed to go to the 5th floor to see the sun terrace (outside the gym) Having a sun terrace in a city hotel is a great idea but the terrace was a bit grim. A few sunbeds on a concrete floor. There was also noise from an air conditioning unit. It could do with a bit of cheering up. What I saw of Chicago was very pleasing, it has something for everyone. Would I go back to the Omni? yes I would. 
