The classes at IIT are difficult but not impossible. When you get to more advanced classes do not be surprised if there are more grad students in the class than undergrads.
The education I received was great. In the work world now, my degree from IIT was a major selling point for me. If you are considering this school, be aware that it is far from a party school, not much social life at all really. Although, like I said, a great education.
Apply for financial aid early. Just about everyone gets some, but there is only so much in the pot and it's first come first serve. Never go south of 35th street if you can help it, and NEVER by yourself. The CTA U-Pass is your best way around the city.