In my experience, the Beijing square Getter 12AX7’s are not only way more reliable but sonically much superior and rich compared to anything from the Shuguang factory…
I have stocked up close to 100 of these NOS and I have yet to have one failure in the last 30 years?
They all test very, very strong on my tube tester and the noise floor is quite low.
You can still find them around, you might pay a little bit more but they last for many, many, many years in the amplifiers I have used them in,
I have a Bogner Ecstasy 100B and it has the original ‘Bogner’ Beijing 12AX7s in it, I replaced all 6 last week with brand new NOS ones and I can’t hear any difference in the tone, They really last.
I bought a bunch of these ruby 12AX7HG Tubes to try out and they sound pretty good but they do not sound ‘as good, as full, as rich and tight’ as the Beijing square getter ones.
The difference is very obvious and anyone would notice doing an A/B comparison.