I can't believe I have shopped at Von's dozens of times and never investigated Windy City. I only found it by using Yelp's nearby function, but now that I have, I will be back.
I tried their Italian Beef sandwich, wet, with mozzarella and giardiniera. The beef was super tender and they get a bonus point for having above-average fries! The staff was friendly and the other food looked great.