I've been following this thread, and particularly the discussions about where to buy them and differences between sources, with some interest. I wanted to share my experience. I bought a set of LinLai E-6SN7 tubes off ebay from seller atop_authentic_auctions. I choose him because of the low price and 30 day return policy with seller paying for returns. I ordered on May 31st and tubes came today. As you can see from the pictures in the link below the tubes were very well packaged and I was particularly impressed by the corner protectors on the box. Logo is horizontal and doesn't say "Global". There is a metal plaque inside the tube with the details and serial number. Tubes came with test scores and were closely matched. I've had them running for less than an hour but they are silent and sound great so far. I have not compared them the the Sophia Electric Blue Glass that I had in my Aric 300B amp before but first impression is they certainly aren't any worse and may be significantly better. I'll do comparison testing after the tubes have burned in for 25-30 hours.
Based on my limited experience so far I would say all of the concern over "Global" branded tubes versus tubes not branded for the overpriced export market is probably misplaced.
https://imgbox.com/gallery/edit/vloWX2Wqf7/2NEwUfO8q0dEOHeR