This tour is great. You can jump on at any of the 13 stops, and as the bus is going along the route, you can get off to explore, and then get back on at the same stop on a different bus later in the day.
You get some fantastic photo opportunities along the way; the best of these is at Navy Pier, which is the 10th stop on the route.
Our tour guide, Jack, was absolutely brilliant and pointed out all the best things to look out for. He was really knowledgeable about the architecture and history of the city, not least pointing out the filming locations of many great films, not least The Dark Knight.
Highly recommended!