Mediocre for the price you pay
I live in Chicago but at times I have to stay in the city for business meetings. Last time I stayed at the Renaissance on Upper Wacker and this time I stayed for a few nights at the Residence Inn. 
The cost varied from night to night and a few nights I paid around 400 dollars. The room was on a high floor so it was quiet and it had a mini kitchen but I did not use it so I can't say it was great.
Toiletries and bathroom really low end and water pressure in the sink dismal. Breakfast in the morning really sub standard and served in disposable plates. Staff tries too hard to please and strike up conversations during breakfast, almost to a superficial level. 
The worst part however were the elevators that took at times an upwards of 7 minutes to show up. My key card stop working a few times and going up and down was a chore at best. Also the house keeping service is terrible (if you ask for something to be brought to your room it will never show up), the front desk has two people working and lines are long. 
I don't intend to stay here again and I would rather go back to the Renaissance paying the same price for a much nicer property.