I enjoyed the Chicago lounge about a month ago. For me, the best features are the luggage storage and the power outlets. It was pretty busy, but I found it calm and quiet upstairs.
Snacks were the same as others mentioned in this thread - I noticed packs of Skittles candy, along with chips.
I miss the sodas and coffee - but during the middle part of the day, a staff member ran a drinks cart under the staircase that offered cocktails, beer, and sodas for sale. I left the station for pizza, and considered shopping the food court level for trip snacks.
Finally, let me add my appreciation for the friendly fellow at the front desk. After I showed him my ticket on my phone, he gave me a card I could "flash" as I went in and out. His announcements over the PA were clear and informative. The time from line-up to our procession to the Chief was short and quick.