I inherited my like new '07 STS this year and it is a pleasure to drive. There are only a few squawks: programming without the nav screen is complex and the drivers seat appears loose (there's a TSB that addresses it) and nitrogen-filled tires are a bit overboard. Aside from those minor criticisms, the car is an excellent performing car. It's rakish looks are complemented by its terrific handling.
No-key locking and engine start. Sound system. Memory seat, climate control, etc., for two drivers. V6 performance and economy.
A little more attention to manufacturing details to prevent problems like the loose drivers seat.