Almost a must :-)

First, very briefly:
The SEL50F18 is a lightweight, well-made lens that is excellent for portraits (umgerechent on full frame corresponds there approximately 75mm / 2.8). The Bokeh is very beautiful, and the sharpness outstanding. The image stabilizer also allows a good use at night and Strassenphotografie. For what it offers, it is very low (please do not compare with full plastic-50s by Canon without image stabilizer, which are disposable). Personally I use the lens in 20-30% of all photos, especially since the kit lenses 1855 and 1650 at 50mm focal length are light little harder and harder subside in the image quality. The low distortion Also panoramic images with high quality can be created, for example by using the free Microsoft ICE An absolute buy recommendation!

And now the long version :-) differentiated:

Advantages and disadvantages:
+ Favorable given image performance and image stabilization
+ Good for portraits
+ Good for night shots
+ High-quality workmanship, stable sun visor
Not suitable for group shots in homes because of the focal length -
- In stark contrast edges and aperture f1.8 purple fringing. This can eg be removed in Lightroom or simply reduce the purple-saturation.
- AF speed with older Nex cameras (5N, 6, 7) in low light very slowly. With A6000 good to update the firmware of the lens (will not be necessary when buying new ones).

Alternatives:
SEL35F18: More expensive, something more suitable for the inside of groups, image quality slightly worse.
Sigma 60 / 2.8: Super sniper already at f2.8 - but that SEL50 is already so sharp that the question is whether that is visible. For portraits also well suited. But has no image stabilizer as not appropriate for the night. In addition, the support for fast autofocus (PDAF) is limited as with all Sigma-prime lenses for E-mount. And 1 stop less bright.
SEL55F18: considerably more expensive, a little better for portraits by longer focal length. Should fewer CAs have fully displayed. But also has no image stabilization, so not suitable for night. This is also suitable for full-frame.

Conclusion: I would buy the SEL50 again and prefer the alternatives. Being able to take photographs at night I have often used and it would be to do without a loss thereon. I have inserted some sample pictures. Have Fun!
About an evaluation of this review, I would be happy :-)