From my interview experience:
The residents pretty much work out of Cook County Hospital, although they do a month rotation at a nearby site in their second year.
Pros:
Extremely busy clinic, you'll definitely be an amazing clinician when you graduate here.
The patient population is extremely poor, often they are illegal immigrants "you don't need to do a medical mission trip because they come to you". YOU are their doctor, and it seemed like they were extremely grateful for everything you do for them (since you are their only access to medical care).
Given the patient population you will see a ridiculous variety of pathology (ie infections, AIDS retinopathy, etc)
The surgical numbers were 2-3x the national average in every category (they give the exact numbers of the graduating class but I didn't write them down)
The attendings were in it to teach and they were genuine in their desire to be teaching in the program and serving the underserved.
You get refractive surgery exposure from one of the attending's private practices.
Residents seemed happy and liked the program
You get to participate in the Chicago lectures that the other programs go to as well.
You're in the best city in the country!
Cons:
Extremely, extremely busy clinic: they told us that they had lessened the number of appointments for the day since it was an interview day and the waiting room was still packed. They made it seem like if you left before 6pm that was a really good day.
There really isn't much time to study, and one of the residents admitted that your OKAPs on the first year might suffer because of it. He said that he did the majority of his studying during the 1 month rotation at a different site.
The entire hospital is a county operation - so the support staff are government employees (enough said

)
Not a lot of peds exposure (that is probably a plus for many) - the residents had no trouble landing solid peds fellowships but during residency they just don't have a huge peds patient base. Program director said he was working on this, though.
I'll be honest that I don't remember what the research opportunities were here so I won't comment on them. This is a great place to train as you will be learning a ton while you're serving a truly needy population.
Hope this helps!