[mapmaker]

There is nothing "wrong" with the five speed. In theory, the more speeds you have in the transmission the better your fuel economy and performance. The ultimate of this is the infinitely variable transmission that you find on some of the hybrid cars. A twelve or fifteen speed transmission would be almost as good but they would not be practical, even in a luxury sedan. By 2006, several luxury brands, Lincoln among them, already had six speeds, so Cadillac followed suit just to keep up. The fancy Toyota with the "L" badge (I'm not going to say their name in this post) already has an eight speed in some of their cars, so Cadillac is behind once again. In the day to day living with the car, there would be very little noticible difference between the five and six speed, so I wouldn't let that be the only deciding factor. As some of the others have already said, a car with other desirable features such as a Navigation system or HUD with a five speed would be better for you than a six speed car without them.