Just got my XTS a month ago, I like the car but not the noise. This is Cadi IV (73 Coupe, 96 STS [the best], 2003 Escalade and this 2013 XTS) and while the gadgets and safety features are nice the noise is disheartening. I can't open the sunroof and expect to hear myself think and even with the sunroof closed the noise from the tires make it hard to carry on a conversation...I'm used to quality Cadillac Quiet. This car is not a Cadillac pure and simple. Even the little 6 Banger engine is noisey. On top of everything else with just a thousand miles on it the engine has a rough idle. It goes in the shop tomorrow for that, hopefully there is a fix for it. Why did I ever let go of my STS.
^ Really, never drove an XTS out on the highway, but I figured it would be one of the quietest cars on the market. I've had some seat time in a 2012 LaCrosse, that thing was a TOMB in terms of ride quality and road noise(and an XTS is a guissied up LaCrosse with more room). It was one of the few cars that I would say was on par(maybe better in terms of ride, depends on how much you like to float) with my old 1995 Fleetwood in terms of isolation.