agree with saxman, I commuted between both DTW and ORD. I can also throw in ATL too. ATL I used DAL ATL on Delta and Southwest, was not a problem and never had to sit in the jumpseat.
To answer your question, I found it easier to get to ORD on UA and then home on Spirit or AA. Without United, that commute would be difficult.
DTW was difficult sometimes because AA would fill up and you don't receive AA benefits being based in DTW. But it was very doable, there was a Skywest flight DFW DTW once a day.
Right out of training, new hires are still going to DTW. You could get ORD before you finish training as well. The most junior FO in DFW is a July 2018 hire.