It's a common question. Many different suppliers mentioned over the years. But, I don't think anyone who has purchased these in lieu of OEM has provided a clear, in depth analysis of any reproductions.
Sure would be nice.
That being said, only the best quality stainless steel will have a "color" and quality when polished, to match chrome. It can be done; but it has to be a very good quality stainless. Not all stainless is equal, far from it. In my photo below, you can see the difference between a reproduction wheel cover (on the right), a thinner stainless stock, and not of the same grade as the OEM. The OEM is on the left; the color is warmer, more close in appearance to chrome plated steel. It also has a very high jewel-like polish finish. At the time I had these repros (long gone) I had a professional buffing wheel, rouge stick and polishing compounds, and try as I might could not get the repros to shine any more. Back they went.
So: not many are talking about their experiences with the reproduction bumper sets and providing detailed comparison photos of reproduction vs OEM.