Very good BBQ, authentic St. Louis style. Loved the sides, BBQ beans and mac and cheese. I prefer the pork to the brisket (against popular opinion) but everything tastes great drenched in the sauce. I was lucky enough to go on Saturday before a rush hit. Check it out if you like BBQ.
UPDATE: The only other things I would add to my experience is that my friend was a little surprised at the location/appearance of the place. I wasn't too shocked, especially when compared to other "BBQ Shack" places, but yes, we did drive past it before we noticed the little black awning that signaled we had arrived. The prices on everything seemed quite reasonable and would not say I left there hungry. The platter dishes (helping of meat with no bread) comes with two sides for $11 (incl. tax), and sandwiches (including one side) just a couple dollars cheaper. They also appear to have a robust catering organization if you needed another option for feeding the masses. If the #2 ranking on Urbanspoon for Chicago restaurants doesn't say it already, the line out the door at 2pm on a Saturday should be enough reason to check it out.