I just got off the phone with Garry of Uncle John's of Richton Park. Yes, it is true that Mack's location is closed for good. Mack is taking a very well deserved retirement, and tending to some health issues. In the city, you still have the Dat Donuts location around 83rd as mentioned upthread.

If you are willing to trek out to the south Suburbs, Garry and crew are really turning out some great product, equal to the original UJs IMO.