Since this first sound paradoxical here my experiences when comparing the two counterparties and reasoning of the decision against the Tamron:
In almost every situation, which was important for me, the Sony is a bit better. Whether it is in low light in video mode or in sunshine.
The Tamron produces nearly the same image quality - but only if you intervene manually!
In program or automatic mode the SONY seems better to match the software of the camera (in my case NEX 5N).
When traveling, we need (the whole family uses the camera) many times the program mode, there remains not the time to make corrections from the moving car. Here the SONY is clearly superior in my opinion. The CA's are with the SONY almost completely corrected when they are at Tamron still clearly visible!
The Tamron then requires a stopping down by about 2 stages. Then the images would also fit. But not in the program mode.
In the distortion the same phenomenon. When SONY virtually complete correction, the Tamron still visible distortion.
In very "dim" light and longer focal lengths I could easily still with the SONY HDR create images, while it was not possible with the Tamron To focus (unfortunately is also not DMF). Only with the Zoom succeeded again. This is probably because the Tamron earlier Aperture 6.3 comes as the SONY!
Here then helps only manual focusing!
The image stabilizer works for pictures at two roughly equivalent - with minimal benefits for the Tamron.
Nor the end - for me two very important aspects - 1.Bildstabilisation and 2.Geräusch in video mode:
to 1 .: The SONY produces a harmonious movement pattern with videos than the Tamron. When correcting the "jitters" are both equally good. But when panning the Tamron tends unfortunately to bucking.
to 2 .: The Tamron has to be zoomed very slow because it is clearly audible during rapid zooming. With quickly I do not really fast, so it would be a dizzy but soon enough normal zoom speed. I can not judge whether this noise would lose over time, but with the SONY, it is already in new condition no problem. It is much more pliable. And practically no longer audible when using the external microphone.
The focus is on two noise not a problem as virtually inaudible.
I would have liked to keep the Tamron, because it is handy and visually better match the NEX. But unfortunately I have to say that Sony (or whoever builds always the SEL 18200) did a good job and I am now but a little more money I invested than initially foreseen.
In my view, the saying applies here: The better is the enemy of good ;-)
The scoring for the Tamron is in my view just below 4 stars but no 3-star rating.
For Sony, I would forgive smooth 5 stars considering the performance of a travel zoom.
If one does not put so much emphasis on the video mode, both are very evenly matched (applies in my view, for resolution, sharpness and color presentation - up to the unloved CA's)!
The perceived quality is both impeccable!
The use of lenses when the flash is I have not tested this since I've bought the NEX 5N to these no longer need. And yet (about 1/2 year) this bill is a complete success!
I hope that my experiences are helpful for other users!
Congratulations to Amazon for the truly perfect delivery service (evening ordered the next morning in the packing station - always incredible!)!