Do you want a real bargain? Go to Amazon and look for a BMW Tourance jacket. They are selling for $275 and that is an absolute steal. It is waterproof and I've really put it through its paces. It includes VERY good armor and a thermal liner that zips out. With the liner in, there is nothing in MO that will hurt you.
Extreme heat is a challenge but then you're looking at the Darien. The Tourance has side vents which the Darien does not. Even with the vents open, anything above 95 is a little rough, but there is nothing that makes 100 really comfortable.
I've had mine for 3 years now and like you, most of my riding is commuting. I did take it to Chile last year and have crashed with it. I still wear it and am absolutely amazed at how well built and versatile this thing is.