Unfortunately, the courses overall in quality are low, but there are a few courses that are worth playing. Anna Page in Rockford is a solid course, as is West Park and Highland in Joliet. Central/Southern Illinois have a few courses worth playing (Centralia and St. Louis courses).
I'd like to add community park in channahon, lincoln park in springfield, and McNaughton in pekin.
And yes, the overall quality especially in the Chicagoland area is not great. But plenty of people consider Lemon Lake to be within the Chicagoland area. That should help the cause, no?