Sophia KT88 vs. Psvane KT88

I might be a tad premature here but I was wondering if anyone has any experience with these new Sophia tubes. I only found out about them a few days ago. I did contact the company and was told they do have a limited supply of KT88's. They said this is a new product for them. They quoted me a price of $400.00/pr. Seems quite steep for new production tubes. The Psvane product is less expensive. Any info you have on personal experience with the Sophia tubes, where they are made, how they compare to the Psvane products etc. would be helpful.