Hi Dandsking,
In case you haven’t read it yet … the first place I would start is the tutorial post here which has all the basic information, steps, and guidelines that can help you make the best possible choice … and avoid the worse ones.
Post #2 and #4 here include the better options I’m aware of in the Chicago area and if I was in reasonable driving distance I would make sure to include Quality Sleep / My Green Mattress which are one of the members here and compete well with the best in the industry in terms of the quality and value of the mattresses they make.
Phoenix