We just got back from 3 nights at the Sofitel. We really have nothing bad or negative to say about it. We've stayed at other higher end hotels in Chicago such as the Park Hyatt, The Peninsula, and The Four Seasons - and the Sofitel tops them all. It's a 4 star hotel with 3 star prices. It's a beautiful hotel all the way around. Staff is uniformly friendly without being patronizing. They were helpful with the one small problem we had and solved it quickly. The common areas are fresh and modern in appearance. The room was very clean with comfortable beds and well-appointed marble-accented baths. My wife loved the huge tub. We had breakfast via roomservice every morning and it was always hot and delicious. The robes and Evian at turndown was always appreciated. The property is ideally situated in the middle of the Gold Coast and all the best shopping and eating is within a short walk. Want a Bentley or latte? They're all close by. This was our second stay since it opened and I'm sure it's to be our home away from home when we are in Chicago. 
