In my opinion the BMW has some advantages. However, I'm slightly biased as you can see by the number of BMW's I have had. That being said the X5 has some other advantages Adaptive M Suspension(including Rear Air Suspension) as opposed to our Cayenne's standard Suspension. While I feel the Cayenne handling is slightly superior, I presume if the Cayenne had PASM (w/o the Air Suspension Option) the handling advantage difference would be more pronounced. In addition, our BMW has summer 40 series tires
in the front and 35 series in the rear, while the Cayenne has all season 45 series tires
Also, I love BMW's free maintenance program which includes brakes and ad-blue. The Porsche requires oil change every 5,000 miles at around $380-400, very costly and inconvenient In addition my local Porsche dealer does not give loaners if you did not purchase a vehicle from them, etc.
Here is my input on the rest:
Road Isolation- Advantage - Porsche -I suspect the 45 series tires
has much to do with this. The BMW can compensate with the Adaptive Suspension settings. But low profile tires
, don't help. Personally, I like to feel the road.
Wind Noise - Advantage - BMW - On the highway while not a LEXUS(not looking for one either), the X5 is extremely quiet and the diesel sound is quieter than the E70 and barely comes thru the cockpit.
Seat Comfort - Advantage - BMW - The BMW's multi contour seat is awesome, with the adjustable upper back support the comfort great. My PCD has 14 way seats- which are not bad, no comparison to the BMW.
Short Distance Preference - Advantage - Porsche - The Porsche feels small in larger spaces, easily maneuverable with power steering plus. Porsche is excellent on the back roads.
Long Distance Preference- No opinion- I have not driven the BMW over 30-40 miles in one sitting yet.
Electronics - Advantage - BMW - The F15 is a tremendous step up from the E70 and the PCD. The iDrive is great, they have come a long way since our 2004 E60 545i. The screen in the BMW is HDTV and the PCD is standard definition. I love how they ambient lighting can be changed. I do not have HUD in the BMW. The Porsche does have the option to place a smaller NAV screen directly in front of the driver. Also, the BMW has LED interior lighting all areas, which is available on the PCD for about $900.
Engine - Advantage - BMW- The F15 diesel is great, especially with the 8 speed transmission. Torque Monster! I felt the PCD was far superior to the E70 and now the F15 is superior to the PCD. On caveat the Porsche diesel is still quieter.
Refinement - hmmmm - Porsche is very well engineered. Based on a older design 2011 vs 2014.
Value - Advantage - BMW- With Porsche's EVERTHING IS AN OPTION business model- our $74K Porsche has less features than our $70K BMW. If you like goodies the BMW is the way to go.
That being said if resale value was a non factor (meaning I could put everything in the PCD that BMW gives) and I could get a PCD that looked like a GTS, I might say PCD. As we know that is not the case so I give it to BMW. I'm glad the BMW offers M Sport on the diesel now.