Several factors went into that decision:

1. My other car is a 911 convertible. Owning two Porsches seemed a bit much, and I have always driven and liked BMWs.

2. The 4.8 with the Sport Package is just the right amount of firmness in the suspension. The Cayenne S without PASM is too squishy (although note that I like pretty stiff suspensions; it was great on the highway though), and with the PASM in sport mode was a bit too stiff. If I didn't already have a sports car I might have liked that, as the Cayenne S in sport mode is a lot of fun to drive. Acceleration was about even, maybe slight edge to the BMW, which surprises me a bit.

3. As all of my music is digitized, the 6FL option was a big selling point. Once they have the glitch worked out, I'm sure I'll like it as it's a great integration.

4. Go back and forth on the styling of the Cayenne. Some days I like it, some not. Really like the styling of the BMW.

5. A comparably equipped BMW was slightly ($5K-8K?) cheaper, although I never really engaged a Porsche dealer on what kind of deal I could get.

In all, fairly close.