This is just my opinion...
Sherman in Skokie - Their service and salesman suck balls but they have good prices and a decent selection.
Fields in Northfield - From what I've heard and with talking to Pat there, they seem like a great place. Pat can help you work out a deal, their on hand selection is a little light but I'm sure they could bring something in and they regularly customize Jeeps at the time of purchase.
With that said, myself, my girl friend, and my best friend all bought our Jeeps at Sherman. If you buy from them, just don't expect to enjoy the process. In hindsight I met salesman there that seemed pretty cool, he drove a Gecko 2 door and was the self-proclaimed "Jeep guy" after I had bought from someone else he threw me a set of Mopar/Jeep grab handles (my best experience with Sherman). Wish I could remember his name but I know where his desk is at and I'm sure if you called and said "The Jeep guy told me to come see him." Someone would probably be able to connect you to him. That's my $.02