This is a lens that is not very well reviewed or researched, and is often mixed up with the Yi Camera Body (20 MP, Micro Four Thirds body, poorly reviewed). Hard to find lens-only reviews. Some forums on DPREVIEW have some positive things to say about the lens (the images look quite good! Not sure about AF speeds....)
DPREVIEW Link --> https://www.dpreview.com/forums/thread/4223027
Album Link with images --> https://www.dpreview.com/gallerie...-lens-test
At the price of $99 including the Macro capabilities, this might be a good backup portrait lens. Plus, with Amazon's extended holiday service window (till 31st Jan 2018) this might be a good first Mirror-less Portrait Lens for some folks (especially if you have an Olympus or Panasonic M43 body)
NOTE : The lens does not allow manual focusing, as the focus "ring" on the lens body is purely cosmetic. Hope some of y'all enjoy this lens!