If you find car services in Chicago to be overpriced, then forget Uber Black altogether.

For airport rides, I usually use American Coach Limousine. They're not the newest of the new cars, nor are the drivers the best dressed compared to other car services you'll pay 2x the price for, but if all you want is a reliable and comfortable ride in an MKT or similar, they're typically just fine. Make sure you reserve in advance. Click the Online Deal tab to save $5. I always book one ways instead of round trips, as then you can save $5 on each.

For a trip from ORD to Highland Park, Uber Black is going to run $90-100, while American Coach Limousine is $60 flat rate.