The Hilton Chicago O'Hare Airport wins for location (since it's literally connected to a terminal), but if you're not in a hurry, I'd say the Hilton Rosemont/Chicago O'Hare is the better airport property. The hotel is very comfortable, has nice public areas, and has a calm and relaxed vibe. I didn't feel like they were just trying to turn me so they could get to the next person like I have at the restaurants and with desk clerks at the Hilton Chicago O'Hare Airport. The rooms are quite and are fairly large. They are also pretty high-tech in that the room key just needs to be held near the lock to open the door (rather than being swiped) and the bathroom lights are on motion detectors. Something I particularly liked is that the bed had flexible LED lights attached to the headboard, so you could focus light precisely where you wanted it. There is no lounge, but there is recognition of status. In my room when I checked in was a welcome letter and welcome amenity (chocolate covered pretzel, water, and piece of fruit).