IMO, the Cayenne is getting pretty dated. Personally I liked the interior of the X5 over the Cayenne and X5's rear legroom was roomier than the Cayenne.

I believe that the Cayenne has a double wishbone suspension setup at the front, just like the X5 but has an optional air suspension to smooth out the ride and be more fit for off-road.

Also note that the Cayenne is heavier than the X5. So the base engine of the Cayenne is slower than the 3.0is of the X5 in a 0-100km sprint.