Hi Peter,
How are you doing at Beyer?
Now to answer you question: Over the years I came to associate products made in Germany, USA, UK, Japan and etc. with better quality control, design and assembly. Products made is China and some other Asian countries tend to be associated with mass produced lower quality products.
I don't make a purchasing decision based on the country of origin so much as on the company that designed and manufactured the product and the quality of the product. It just happens that most of the headphones that I choose to buy are made in Japan and Germany.
With that out of the way it really depends how the products are made. There are many Chinese companies that make very good quality products and some European companies that made products that suck. I think the concern is that if let's say, I buy an AT headphone that is made in China it would be made of lower quality parts and at a cost point that will prevent it from reaching its designed potential. But if you think about it the same can be true for the product made in any country.
Traditionally European (Mb Quart, Beyer, AKG etc.) and Japanese (Stax, Fostex, Yamaha etc.) manufactured products tend be to associated with better quality and the higher-end products are made in these countries. Can they be made in China with the same quality control? Well that will depend on who is making it in China. The reason for the company to move the manufacture process to China would be to cut cost, when you cut cost you would most likely cut quality. Now, imagine, a young Chinese company designs and makes its own high end product, it's a hand made new headphone. In this scenario you would expect good quality and country of manufacture should ideally make no difference. To summarize, I would expect products of specialized companies like Stax, MB Quart etc. to be made in their countries of origin, and attempt to make it in China would be interpreted as an attempt to cut cost and ultimately something that will lead to lower quality.
Based on what I explained above, in the end, I would pay premium for a top of the line product if it's made in Japan by Stax and I would be reluctant to even buy said product if it would be made someplace else. I hope I answered your question.