I have a vk4 i bought from AliExpress. I would pay the sort of money they are asking for. But you're right. Everything else in the price range seems to be out of stock. Personally cca cst is my favourite in this range. If you're looking for an audiophile brand name, fiio jd3 is one option. Else Xiaomi dual driver is also quite decent, particularly when you look at the price. Only good thing about the qkz is that it comes with a detachable cable and looks fancy