I do the Chicago run every month-and-a-half or so. It's always comfy and a great place to catch up on reading or whatever program I'm into. The high-speed portion has cut a fair amount of time, but it's not uncommon for the train to be 15 minutes late, often more in the winter or if you get stuck behind a freight train. Still, I wouldn't trade it for driving.

(as other people have said, Guest Rewards usually works just fine)