I traded in my 2003 CTS for my current 2006 STS, and LOVE IT! There is no comparison between the two cars. It is the best car I've ever owned. I'm always learning something new about the STS. I don't know how they can make this car any better. I advise everyone to take a test drive in the new STS, you'll fall in love with it.
My favorite feature? I think everything is great, I guess one thing that is "neat" to me is if the battery is out in my fob, there is a connection slot so the car will start. I love the heated backseats, steering wheel, and push start button. I love all those buttons.
I wish the navation would turn into a monitor and there was a way to see what whats behind you when you put the car in reverse. I've already had to replace a left turn signal and can't seem to keep all four tires at the same air count. My dealership sends out coupons that can't be used for the STS.