The cars you list are:Cadillac XT5 or XT6, Audi Q8, Q7, and maybe Q5 and Jeep Grand Cherokee
First, elminate the Jeep. Their reliability is horrible and even worse it seems since Fiat took it over. This is according to everything online including Consumer Reports.
Next up is Cadillac. Better than Jeep, but they do have a lot of electrical issues. The only saving grace is the CT6 is based on the same platform as the Buick Enclave, GMC Arcadia, and Chevrolet Traverse. They are all based on the new GM C1 platform of different lengths. Electrical issues have been reported but the power train generally speaking is fine.
Last comes the Audi. They have been working on their reliablity for some time now. Still not as good as Lexus, but it is better than the above options. If you are restircting yourself to these options, it is the most reliable brand. Since you already found one at discount I would go with that.
Best of luck.