Bought last December (2015) when KEF had a sale. They said "factory recertified" but in no way could I find any evidence of them ever having been out of the original box. All the little sealed plastic bags on the cables, 1/4" adapter, airplane adapter and headphones themselves were intact. Half price, $149.50.
Notice that the KEF M500 (and M400, I believe) are an "on ear" design and not in-ear or over-ear type. They are supremely comfortable for sitting and listening, but because they don't cup the ear like an over-ear type they can slip off with not a lot of movement. Definitely a "listen only" product and not "action oriented."
As for sound, they remind me very much of my R series speakers in that they are very linear, smooth and without any bass peaks, midrange dips or treble boost. They are just a little more capable of higher frequency than the Uni-Q on my R500 speakers, and certainly go deeper. They can't compete with a bass-strong set, but that's exactly what I had hoped for. I really like them!
