i received interview invites from all the university-based chicago programs. i think as long as you do reasonably well on step 1 (say 220 or better) and did well clinically with good letters, you should be able to eke interivews at each site. many of the chicago programs are currently in flux. i would think about the following:
1) do you want to research?
2) are you considering subspecializing?
3) are you considering academic vs. private practice?
4) what kind of patient population do you want?
u of c has a long academic tradition, is smaller, harder to get into even with a research background. has the better gi division but not good in hepatology.
nu tends to be in flux more so from year to year, is beefing up its research options, now a ward-based system but some say you will still encounter well-to-do patients. some say may has the better hem/onc division and hepatology.
uic has a very good patient population and is clinically focused and does not offer much research. shares the chicago va with northwestern...still not sure how that has worked out. uic still has priority there, i think.
rush has many private patients and attendings. rush has insanely happy residents. not sure about research.
loyola is an up-and-coming program, has its own va, and probably has the best cardiology division in the city.
rheumatology is not the best in any of the chicago programs. northwestern has the largest division but u of c is ranked high in research with its ties to the immunology/basic sciences departments.