A friend and I are on a quest to try lots of tavern pizzas in Chicago. We really liked Side Street Saloon and were very underwhelmed by Michael's. I have no idea why Michael's gets the rave reviews it does. It was a cardboard crust and sauce from a can.
So far my favorites aren't really tavern style at all, but more Neapolitan or New York: Robert's in Streeterville, Pizza Lobo in Andersonville, and Bungalow by Middle Brow in Logan Square.
For actual tavern style, call me basic but I think Lou Malnati's thin crust is hard to beat.