It's been two years since the 28/1.8 appeared, and two years is an eternity for Viltrox, The aperture ring is well made on that one, a little stiff for video use probably; they figure most will use the A setting.
What Cosina and Thypoch have done is established a new reference point for high end 28s - fast apertures and low weight. 28s are surprisingly good for bokeh work.
Their glass formulations provide similar highlight handling to that of the Thypoch lenses, and that is a great asset for people photography - the Chinese are not so risk-averse for that niche, in social settings. They can stick to f2 for very light weight, and use the CV 28/2 APO as the target to surpass.