Frosted glass provides all the benefits of normal glass, except gloss. This means that it is more resistant to scratches and does not collect fingerprints and smudges. Here's what it looks like (Sony Xperia Z5): One disadvantage is that the colors look a little dull, but I'm willing to take that compromise if it means my phone won't look like dog crap in three months. On the other hand, unpolished stainless steel is one that was used in the frames of the iPhone 4 and 4S. It looks more like anodized aluminum, unlike the ones used in iPhone X/XS/XS Max where it's glossy as hell and can peel off and accumulate microscratches over time. What do you think?