There are just a few reviews of this lens out there, but they are enough to generate good expectations.
One thing that those reviews mention is that the lens is completely made of plastic and it feels kind of cheap. However, the lens has a better build quality than I expected and it does not feel that "plasticky". Also, the lens hood is thick enough and feels well build. It is lightweight though.

Now let's talk about its performance.
Autofocus: My first impression of using this lens on my a6300 for video and photos is that its autofocus works way better than I expected. It's not as fast as native Sony lenses, but it makes a good job. In extreme conditions of light (too bright or too dark) the lens may doubt itself a few millisecond, but in the end, it can focus even in those situations.

Image quality: I'm not an expert in this field, however, in just a few words I can say that in the usual means of photo and video visualization you won't notice you are using a budget lens. Taking into account the results you can get with that wide aperture and 50mm, you will get pretty professional-like results using this lens in photos and videos.

I consider this lens is a definite "buy". It has a similar price to some budget prime manual lenses, but with this Yongnuo, you are getting not only good image quality but also autofocus capability.