This a very subjective and murky topic. And there have been countless discussions on the internet over the years concerning new production vs. NOS tubes, where there seems to be a few main camps of thought. First camp says that NOS can be superior both in durability and in sonics. Second says that it's only really about durability. Third says that there is practically no difference. Also, it seems that some new production tubes have very different electrical characteristics than their names imply, such as JJ new production of some American style tubes. But even when looking at it from a perspective of a few main camps, it is still all very vague and murky. Which specific new production and NOS tubes have been directly compared? Which specific durability and sonic issues were observed between them? Without specifics, it's all pretty meaningless chatter, i.e, NOS sounds better, is a packed statement that needs unraveling to carry any real meaning. What has been your specific comparisons and observations between new production and NOS tubes? Did you observe more or less noise? What type of noise? Rattle, microphonics, hiss? Did you observe a different frequency response? In what way? More or less lows, low mids, upper mids, highs? A difference in breakup? In what way? A difference in 'dimension'? What does that term mean to you?