I have a pair of Rainlegs, and they're great---if you're wearing shorts. I don't think they would work with pants, because they're just about knicker length. The problem I see with wearing rain pants, no matter which type, over work pants is SWEAT. Chicago isn't exactly cool in the summer, and if you're pedalling any distance while wearing rain pants you will drench your pants with sweat.

The Outlier pants are probably the best option, but they're way expensive. Lanolizing a pair of wool pants sounds like an interesting. Of course, you're not dealing with just water when you ride in the rain. There's also road grime.