Radisson Blu me away
This is a great property. One of the best hotels in Chicago, if not the U.S. Very few hotels make everything work and when they do it is typically an expensive experience. The Radisson Blu Aqua is able to provide an amazing experience at an outstanding value. 
The hotel is in a great location, within walking distance (or short cab ride) to many attractions. The hotel is absolutely stunning both inside and out. The lobby is gorgeous, and you can tell the rooms are new with beautiful decor, and excellent amenities. The view from our room, 1723, was amazing with the Navy Pier and lake views on one window, and Millennium Park on the other. 
I stayed in a business class room and have to admit this is was on of the best lounge experiences I have had. The lounge was never crowded with a decent selection of drinks and snacks. They even will loan you an ipad for your stay. 
All that being said, what makes this hotel amazing is the staff. From wishing my wife happy birthday at check-in (I had put a note when making the reservation) to consistent smiles and friendly attitudes the Radisson Blu has a superb staff. As an example, one evening we were in the lounge and attendant, Scott, asked us what brought us to Chicago. I mentioned we were going to a concert for my wife's birthday, casually mentioning the band we were going to see and the location. The next day we ran into Scott, and not only did he remember us but specifically made a point to ask us how we enjoyed the concert and the venue. Talk about service! 
I'd highly recommend this hotel to anyone. There is a reason all of the reviews on here are superb, this is a world class hotel.