I can only tell you my experience with my own 2012 X5 35d. I ordered it new. It is now 2 years and 2 months old and two minor things have gone wrong with it: A tail light had a lose connector that I fixed myself and the air conditioner fan switch had a lose connector that the dealer fixed. It now has 43K miles and it has performed flawlessly including a round trip to Alaska where we encounter a few challenging road conditions. My overall fuel consumption over 8K + miles to Alaska and back was 24.7 mpg. The torque of this engine is addictive, the noise the engine makes is much louder than the competition and the steering is heavy but precise. Oh, and the navigator is worthless but that goes for my F10 too.
I recommend you get one with Adaptive Drive. It makes a world of difference in the ride and especially the handling department
Diesels with Adaptive Drive are very rare because they were special ordered only and this was a $3,500 option when I bought mine.