Great if you love a delay! *sarcasm* (And Garrett Popcorn. Not sarcasm.)
American Airlines & United Airlines hub. (I've also flown Delta, Frontier, Alaska.)
Current Grade: C- (August 2019)
I read somewhere that O’Hare has the most delays of any American airport. They blame in on that Midwest weather, or something. Anecdotally... it’s incredibly rare to fly here delay-free. I used to fly from O’Hare to Rochester every Monday, and lived in Chicago for six years, so this is not mere cursory airport exposure. In fact, my first-ever memory of a flight delay was a six hour layover when I was about eleven and my poor grandmother had to entertain me in these hallowed halls on our way to Austin to visit my cousins. There’s one corridor between terminals 2 and 3 that reminds me of her and her patience/courage. I've met friends during flight delays because it's a massive hub and someone's always sitting in O'Hare.
There's good natural light in some of the terminals and most of the walkways between terminals. I'll give them that. And the United light show on the moving walkway is a good time. Plus they play a mutated Rhapsody in Blue which really should be associated only with New York City but I'll take my Gershwin wherever if I'm being honest.
The Garrett Popcorn is always worth it and easily walkable - there's one in Terminal 1 near gate B8 that opens at 6am. Don't worry about why I know they open at 6am.
Good connection to the Blue Line CTA. Also of note, the CTA now lets you Apple Pay your way onto some of the station platforms so you don't even have to stop at the kiosk to buy a card. The future! Love ya Chicago.
C- but I have had fun in this airport before.