The Kimpton Gray is a nice hotel and it has a great bar (Vol. 39), but the quality of the location depends on your reason for visiting. It's in the middle of the Loop (our business district), so it is extremely convenient for transit and business travel, but the area is dead quiet at night without much to do. But it's an easy walk to some of the major tourist attractions like the Art Institute and Millennium Park.

The Intercontinental is on the border between River North and Streeterville, located on the Mag Mile. This would be my choice if you are visiting for leisure, as it will be a better area to walk around on the weekends and nights with more to eat/see/do in that immediate area. Still an easy walk to Orange/Blue line trains if you are commuting from the airport on the train, and the Brown/Red line trains to access the rest of the city.