While it goes much better before 6 AM on a Sunday, most of the time I hit this stretch of I-80/I-90/I-94 between 10 AM and 2 PM. Traffic is typically heavy and moving at or above speed limits, from I-55 to Portage (or Benton Harbor if you are going on into Michigan). Driving can be intense, because traffic is moving fast.
There are other times of day that congestion from commuter traffic will slow things to a crawl (and all it takes is one stupid move causing an accident).
For what it is worth, you do not go through Chicago on I-80, this is the bypass. I-88 and I-90 go through, and those are a lot more pain. I know, I lived on the north side for several years and had to go out east and west often.
Going into Michigan, I-94 from Portage to Benton Harbor is a lot more crazy, with traffic speeds from just under the speed limit to over 100 mph. I settle into the right lane to move with the big trucks.
Tom Test
Itasca Spirit 29B