Akira, any tool in your hands will be handled by a master 
Nevertheless, I would like to hear your experiences and why you got yourself a D750
Did I mis anything or is this your first public mentioning your return to Nikon?
As you might have guessed, very curious what made you decide to do so
My comment above was indeed my first announcement of returning to Nikon, and FX.
The biggest reason for my return is almost exactly described in the articles Andy linked. So, this thread is very timely for me.
I've been using m4/3 system on and off for nearly seven years. I still like them for what they offer. But maybe I become tired of the images created by stuffing much resolution into a tiny sensor. I didn't get any 3-D feel I always cherish, even with the images with the shallowest DOF I could achieve.
The resolution of an FX format 24MP sensor corresponds to that of a DX format 10MP sensor which is almost the same as that of D200. I haven't owned or used D200, but after seeing many excellent images taken with the camera and revisiting some of the favorite images of mine taken with the cameras of even lower resolution (D2H and D40), I realized their smooth, round and 3-D renditions. D200, D40 and D2H are cameras of very low resolution by today's standard, but their resolution was actually high enough for most purposes. I still remember Bjørn's review of D1 whose 2.7MP sensor (don't miss the decimal point!) outperformed 135 format Fuji Velvia.
An FX camera with the 16MP sensor would make more sense in this context, but neither Df or D4s was within my budget. I remember I really loved the rendition of the 24MP sensor of D610, but didn't like the fact that the customization of the buttons (especially the OK button) was limited and its AF performance is not satisfactory to me. That's why I setteled on D750. I love this newly designed grip, too!
There are other important reasons, but these are the main ones for my return to FX that relate to the articles.
