Definitely not - the 50/1.8 build quality (two pieces of glass helpd together by a cheap plastic barrel) will be still horrible, as will the noisy an imprecise af motor. I had bad experiences esp. when the zoom mechanism pushes the interior outside - bump against anything, and that's that.
That isn't salvaged by the bokeh going from "horrible" to "below average", in the best case to be expected, that is. This one is build and designed for the local Asian market.
Of course, the f1.4 is possibly of more interrest once they get round to shipping it...
Indeed, a 50/1.4 clone at a very cheap price would be tempting to have around just for the low light capability when in a pinch (like night time photography). For everything else, there are better options around nowadays unless you're on an ultra-low budget and don't worry about af precision.
However, as this has to be imported from China I'd have to pay 20% vat plus 20% customs (Germany/EU), so unless you try to circumvent customs altogether it isn't such a great offer anymore vs. a used Canon 50/1.4 bought locally. And it's not like there would be any good warranty service to be expected from Yn.