A QP450 and a K701 are totally different headphones. First off, the QP450 is CLOSED. The open version of the same, the QP400, has circulated around head-fi a bit in the form of a pair that was at some point in the possession of both Highflyin9 and Nikongod. I recall they both said good things, but not K701 good. I had a QP95, the nearly-identical predecessor to the QP400, which I reviewed here and which last I saw was for sale on ebay from the guy I sold it to for around $100. I sure wouldn't pay 219 euros for a pair of them.
I've never heard a 450, mainly because when Willi Pressuti offered to let me borrow one (along with the possibly even better QP805 HS), I said no, thinking it would bias me too much, and I didn't want head-fiers to think I was a marketing guy for MB. Now I'm kicking myself, as head-fi is full of people with "review" pairs and amps from various manufacturers. Live and learn.