Just how good are these? I realise that is a very open question as it'll come down to personal opinion and the official thread on these might be pretty biased . Would these be an upgrade over my K7XX's? Whilst I enjoy listening to them I find them uncomfortable after awhile and if I was to sell them on to fund the HD650's then I've had my money's worth out of them. Then comes the decision what to power them with as I'm still rocking the Vali 1.