I dunno folks, I don't think you can compare the two.
The reasons why the Mustang is better are as follows.
The Mustang is much cheaper, and almost has the same performance.
The Mustang is a sexy coupe. The Cadillac is not. Believe me, all those stealthy angles will look very dated very quickly, wheras the Mustang proves that an older, but classic look is what will stand the test of time.
All those sophisticated electronics will wind up failing. One of the best things about the Mustang is it's inherent simplicity. It's touch screen based dual zone automatic climate control system will never fail because it doesn't have one...