Is there any real difference for survival purposes in first-surface (reflective coating on the front) and second-surface mirrors (reflective coating behind the glass)?

I am surprised that Corning, with all its experience in glass and ceramics hasn't come out with something useful, highly reflective, and unbreakable (or nearly so). They do so much for optics and space materials that one might think they would have something, and we just haven't heard about it.

Sue