Excellent hotel
I stayed here recently during a week when everything downtown was double to triple the normal weekday price or sold out. I chose this hotel because of its proximity to the Blue Line CTA train to downtown and am very happy. I will probably come back here again as a backup when the downtown hotels start to do that crazy filling up thing. I timed it on foot as a 50 minute transit to the Jackson station downtown. Thats 10 minutes walk to the Cumberland station through the parking lot (easy to find, the staff will show you) an average of a 2-3 minute wait for a train, and then a 37 minute train ride. There is not much around this hotel within walking distance though. 
The hotel is new, clean and modern. The suites are refreshing when you are used to being in a typical hotel room. Large steam showers, nicely sized living room, and large comfortable beds. The closet is a little small, but plenty of room for 1 person. I love that this hotel has a full length mirror. Why do so many hotels leave that out? There is a small refrigerator in the room, but it did not have a freezer section in it. The staff is awesome here, but I did notice there were some large groups staying here which kept it busy. The lobby bar was packed almost every night. There is a full Starbucks shop next to the front desk, which is frequented by many of the local office building workers. My only complaint of the room was that the thermostat was not digital. It was a slider style that controlled both rooms and it took some constant adjusting to get the right temp. 
The concierge lounge had a nice rotating assortment of goodies, salads, pasta salads, cheese/crackers and fruit. It was staffed with one attendant and he was very polite and professional. He even remembers the preferrences of frequent guests and those that stay for multiple nights in a row. One word of caution though, is this lounge is good sized, but does not have a ton of seating, probably about 24. For a popular hotel of this size with lots of elite Marriott guests, two of the three mornings for breakfast, there was no room to sit. The breakfast items had some variety and everything seemed fresh and well prepared.