A few of my first images were done on small, pure silver plates and they worked fine. The electroplated plates I moved to were faster and I think polishing was in fact the culprit. Though whether that had to do with hardness or more polishing experience, I cannot say.
I personally liked starting with pure silver plates. It was one less equipment related issue to deal with before working with images. In the end though, pure silver plates are more expensive and tricky to polish without bending if you work with thinner stock (I was using 22 or 24 ga. fine silver).