KGB , I just priced a CLE-SLC roundtrip in Economy for random dates in January (14-22). For the Delta nonstop in each direction (or for connections), you would pay 50,000 Delta SkyMiles plus $11.20. For a connecting-flight itinerary on AA, this is what you would pay:
Much longer travel time in each direction, of course. But the cost savings -- especially if you want to use miles -- can be substantial if you go with AA. Both Barclays and Citi offer generous sign-up bonuses on their AA cards.
Also, although Amex MR points do not transfer to AA, they do transfer to some of AA's oneworld partners, so you might still be able to use your MR points for award travel on AA (subject to AA's making the needed award seats available for partner redemption). For award redemptions involving connecting flights on AA, Cathay Pacific might be your best transfer option.