OK i got the Kef m500 today, two days delivery from amazon.
Let's start with saying that they don't slip as much as i was scared they would.Their clamp is fine and they are absolutely ok to walk around or twist the head (i have average/small head).
They look FANTASTIC! Really, guys, these headphone are real beauties (and they are probably one of the best looking headphones i've ever seen (classy and modern at the same time). The construction quality is sturdy and even the case is looking good and it should offer good protection.
I had the chance to test them briefly in my lunch break and the sound seems to match the look: The sound VERY VERY,VERY good.
I can't wait to go back home and give them a good listening.
Maybe they will have a special place in my headphones collection
At the moment very happy with the purchase