Huge Convention Hotel
What can I add to the more than thousand reviews already written? No arguments on excellent location. This is the (probably) largest hotel in Chicago. It is a convention hotel. I stayed during one of the largest conventions in the city. Not a member of Hyatt program.
The hotel was full, but check in was fast at night. I was lucky that my rate negotiated by the travel agency included internet otherwise would have been a $15/day, which is unfortunate. A convention / business hotel should include the internet. My breakfast was included but I had to skip it 2 days as the lines were too long. What was really obnoxious was $25 charge if you placed any personal items in the minibar! That is ludicrous. Most hotels leave a small space for personal items. 
The bed was ok. If you select the corner rooms they offer a little more space. The bathrooms I would grade as below average for a hotel of this size. The personal shelf space was minimal, and no bath-robe (should be standard at this level). 
The hotel is connected via skyways and passages to Illinois center next door and then a small mall with multiple fast food outlets, LensCrafter, Dunkin Donuts and a CVS that you don't have to go outside for great esp in the winter/rain. Two AMC cinemas are within walking distance
Overall you are paying for the location. Average for everything and I give it poor marks for internet price, putting your stuff in mini-bar pentalty.