I just picked up my GS 450h last week and can already say that I love the car. The performance is amazing and I give Lexus high marks for the quality of the car. I traded in a 2002 GS 430, which I was extremely happy with, but this car has it beat in every category. This is the most fun I've had driving a car.
My favorite feature has to be being able to do everything without taking the key out of my pocket.
The aux. input in the center console is hard to reach. It seems like it should have been put in the front of the console rather than the rear.