I can tell you first hand. When I got my CTS-V, the new M5's weren't out, and the old ones were way too expensive, because the new ones were outrageously priced. And, there is something a little seductive about cam lope at idle, and growl at throttle.

The interior took a little getting used to, no question (I traded my X5 4.4 for this car). Too much metal in there for my taste.

As far as performance, it's top notch. It sticks in corners like few other cars. When you get into it, it just flat out hauls butt. And, shifting gears the good old fashioned way is pretty fun too.

With the LS6 that I have, it is easily moddable. There any number of power adders available, that are a fraction of the price of BMW power adders. It's not too hard to get 500 hp in this car, and there are several around over 600. Not bad for a family haul mobile. For about 6k, you can easily be over 500 hp.

The STS-V is another car entirely. Cadillac thinks it competes with the new M5. Recently, I hurt my leg pretty good, and wasn't sure if I would ever be able to drive a stick again. I considered the STS-V for about 4 seconds. The supercharger, I hear, kicks in with a bang, but they softened the steering and suspension too much.

My car sat in my driveway for 3 months, because I simply could not come up with something better to get. I've had it for 2 years, and will probably trade out of it in the fall. Now that I'm healing, and driving the V again, I'm having fun with it again.

It's hard for BMW people to think there is any appeal. The styling - you like it or you don't. I go both ways on it honestly.

All in all, it's a lot of car for that money.