I have a D3x (same 24MP), it is considered as a great camera, with no problems (apart the price )... At f/22 I'm sure I have more spots then on that picture !!! Sure, I clean it from time to time and give it to my shop twice a year for a more complete overhaul (lost a screw recently, surprised me), but I use primes, change lens often and know that dust is a fact of life in digital photography (and don't get me started on film spots and scratches )! The best oil spot I've had was when mounting the brand new out of the box 105 Micro VR, when I pressed the AF-On button, I literarily saw the damn thing coming at me in the viewfinder, I almost ducked by reflex, and there it was on the captor for me to clean !!!!
Since I've given all my lenses to clean, and clean them myself in between... And surprise... Much less annoying spots (but I'll always find some at f/22)