<p>I have some mirrorless cameras in addittion to D300 and D700: The Nikon V1 and the Panasonic GF-1.<br>
Regarding your points:<br>
1. I see difference in image quality on all of them, but for small photos on web or in photo books it is not enough to make a difference to me.<br>
2. I see why Nikon has gone for CX: It is small enough to be conciderably smaller than DX. I feel DX and micro 4/3 is so close that for the lenses there are not enough difference to go for the smaller sensor. Mirrorless cameras will of cause be smaller than DX/FX, but that is just one part of the kit. I do not find the CX format has too small lenses and camera bodies.<br>
3. I still like having a viewfinder, and the GF-1 and V1 viewfinders are not as good as an optical.<br>
4. Same here - serious shooting is done with DX/FX - family snaps with CX.<br>
5. I have the lens adaptor for the V1, and the possibility of converting lenses to super telephoto is sometimes nice. But, I do not use it as often as I tought I would.<br>
6. Since I am used to Nikon DSLR menus I also prefer them for familarity. Not sure they can not be improved, though.....<br>
7. 4/3 ratio I also can not get to grips with. I almost always end up cropping in postprocessing. But, a lot of my images end up in 1/1 squares anyway.</p>
<p>I treat the V1 and GF-1 cameras as 'compacts' and for that I find they do a tremendous job - much better than any smaller, traditional compacts. I would never (for now...?) ever concider selling my DX/FX and go fully mirrorless. But that is just me...</p>