There is a definite quality difference between the older selp1650 and the newer ones. Ive had both. The older one was very quite but the image quality was not the best. The new one i have was manufactured less than a 6 months ago and it makes a bit of noise while zooming and "unpancaking" but the image quality is far better than the the first one i had.
kind of odd.
However,,,, none of them can compare to the SAL1650 f2.8 that lens is just amazing at anything above 18mm. but it's HUGE especially with the adapter.
If you get the sel18105g, You'll enjoy it's fixed barrel length but your 18mm shot camera jpegs will be heavily cropped by the camera. I did a wedding once using that lens. i ended up having to do a lot of raw editing. But on the plus side the lens works very well in video mode.
Also you will notice that the a6000 actually has a tad better sensor that the nex7. But not worth worrying about. The NEx7 has a all metal body which is nice.
The nex-7 also had the old Minolta/Sony flash mount.