I drove the Cayenne Diesel again today and can not believe how smoothly it handles. The X5 handles well too, but I think the Cayenne is better. I was going 80 mph and it did not even feel that fast. This Cayenne had the blind spot system and that was definitely a useful feature.
The interior of the X5 seems bigger, but both SUV's seems small compared to our Merc GL350 that we would be trading in.
I am just not sure if the Cayenne is worth $10k-$12k more that the X5 we were considering.