It's a wonderful vehicle. I have the rear wheel drive vehicle and the performance in the snow is still good. It is excellent in rainy weather. Cadillac's traction control makes up about for the lack of all wheel drive. But, if you drive in heavy snow go for the all wheel drive.
The powerful zip on take off...this 6 cylinder vehicle is more powerful than any 8 cylinder I've ever driven.
Make all STS vehicles with all wheel drive...it will make for the perfect car.