I'd quibble on the value for money rating - particularly as the pads and lead aren't replaceable.
My trusty old Sennheiser HD497s were only 50 quid (albeit 10+ years ago) and would be on a tip by now if I hadn't been able to replce both lead and pads. And they still sound great to me (esp playing vinyl
It's surely unforgivable at the 500 quid price range to have parts with a high likliehood of wear and tear not be user replaceable. (?)