I completed a one-night stay at the Sheraton O'Hare with a Park and Fly package. As an all-suite hotel, the rooms are huge. Moreover, the hotel was clearly renovated and the furniture was mostly in great condition. Despite it's proximity to the airport, the building's insulation and Sheraton's trademark beds made it easy to sleep easy for an early flight the next morning. The shuttle both to/from the airport was prompt and with a convenient schedule (expect a shuttle every 20-30 minutes).
Two minor housekeeping details: (1) a glass from a previous guest was left outside my room and never picked up during my stay and (2) one of the bedside lamps didn't work and had a broken socket. Nevertheless, I wouldn't hesitate to stay at this hotel for another pre-flight stay.