How consistent are the trains in Chicago? Are they often late?

I don't have a ton of experience on the Metra, but I take the CTA every day, and it's fairly consistent. Sure, it's late on occasion, but usually not by much. The trains are fairly regular, so if you miss one you don't wait too long for another. Well, when you have that many trains going even if there's a delay it's not too bad. THey may not run like clockwork, but it's good.