Bar none, the AVVT 300B-C37 is my favorite 300B. Others worth consideration are the Emission Labs 300B and 300BXLS as well as the Western Electric 300Bs. I like the KR 300BXLS in amps that can use it to its full potential, but I do not like it as a standard 300B.
Sophia's "mesh" tube is a Chinese relabel (from all accounts, it's a TJ/Full Music). These wannabe-meshes are decent tubes. They're grainless with good dynamic extension. My problem with these tubes it their distant and unimpressive midrange. All the pairs I've tried (whether it be Sophia or TJ) were the same. I really do believe people are so enamored with these tubes because of the pretty lights.
Sophia's "mesh" tube is a Chinese relabel (from all accounts, it's a TJ/Full Music). These wannabe-meshes are decent tubes. They're grainless with good dynamic extension. My problem with these tubes it their distant and unimpressive midrange. All the pairs I've tried (whether it be Sophia or TJ) were the same. I really do believe people are so enamored with these tubes because of the pretty lights.