Superb location and an enjoyable stay.
The Hotel Monaco is a very nice, centrally located hotel (you can walk almost anywhere from there). I asked for a river room view and was delighted to find that my room not only faced the Chicago River, but it had a window seat! I passed a good hour comfortably (the window seat has cushy pillows, too) watching the river, boat, people and Chicago life from my 8th floor perch. 
The room itself was a good size, with enough closet space, a well equipped bathroom, a nice size desk and chair, and an up-to-date tv (I didn't turn it on but it looked new). The bed was comfortable and there were plenty of pillows. They even got my "no feather" request right the first time! The rug, however, was a dark burgundy with black swirls -- not my taste, but not bad.
The lobby was comfortable, with plenty of chairs and sofas, as well as a fake fire (it was 72 degrees the day/night I was there). That said, it was packed around cocktail hour (free wine in the lobby at 5pm); I didn't take part in the festivities but everyone looked like they were having a fine (not too rowdy) time.
The staff were friendly and efficient , if just the smallest bit overwhelmed. This was the "NATO" weekend in Chicago, and they seemed to be fully booked -- people were coming and going all at once. Still, they were pleasant and helpful.
I was there for business, but also attended a performance of "The Iceman Cometh," (brilliant!) at the Goodman Theatre, which is just a 5 minutes walk from the Monaco. Although I do travel to Chicago yearly, this was my first stay here -- it will not be the last.