Having driven most of I-86 and all of I-88 recently going to Vermont, it's not a bad route. The cops weren't out much when we went, the traffic wasn't a rat race like I-90 is, and the scenery was okay. I've also driven that route dozens of times so it was routine. I-90 isn't an option where I am due to living 5 minutes off of I-86.
Reasons to go I-88/86: Lighter traffic, more scenery, there are turns in the road, and no tolls.
Reasons to go I-90: Faster due to prevailing traffic, regular stops right off the interstate, better paved.