Potbelly and Manny's are good food choices. But WiFi's crap. Chances are you won't be able get on the overloaded "Free Public WiFi" and the paid Boingo WiFi is very buggy. BYO hotspot.
Midway/southwest has the slowest baggage claim on earth. If you are flying into Chicago and can avoid checking luggage, you will save yourself a lot of time waiting!