I bought my '05 CTS about 3 months ago. I certainly was impressed with the performance when I test drove it, but now that I'm living with the car on a day to day level, it had exceeded my expectations. It's not only a good daily driver, but is a great weekender sports sedan for those winding, mountain roads.
Favorite feature is the selectable transmission modes that come with the 5-speed auto. Normal is good for economy, but the "S" mode is good for pleasure (performance) driving.
The interior could use some better appointments and trim.