I have stayed at both the Westin and Sheraton ORD and was persuaded not to try the 4 Points. I am very pleased with the Westin, although it wasnt the best stay, it was just a one-nighter and so I dun really care. The rooms were reasonably furnished and the service was mediocre.
The Sheraton on the other hand is much more dilapidated on the inside than the outside. As a gold, I was upgraded to the club floor at the Sheraton but the room, although large, is very much old and shabby.