With the automotive world giving such panegyrical reviews to this car, I figured it surely must be a ploy to get us to stimulate the economy and buy American. Prior to my '09 CTS, I owned a 2008 Acura TL Type-S that was my absolute favorite car. However, I drove the CTS, and it was all over. My 3.6 DI AWD is a real driver's car; it gives great feedback to the driver, corners like it's on rails, the brakes are phenomenal, and it has admirable throttle response. Not to mention great style! Overall build quality is great - no complaints in the first 7000 miles. I would recommend that anyone in the market check out the CTS among the typical mix of imports - you'll be pleasantly surprised.
Overall handling, interior styling, *Fast* GPS, iPod integration, braking, AWD system, adaptive front lighting, UltraView sunroof... just an amazing car!
More POIs in the Navi, quieter cabin (although not bad as-is), more supportive seats for those of us with (ahem) wider seats.