One of the reasons why you will find a wide variety of opinions on vintage tubes comes from the fact that most tubes sold as NOS are really just old tubes where the amount of prior use is unknown and wildly variable. Even when someone has "tested" the tube, that does not say very much as most tube testers can do little more than tell you if a tube is near dead or not (something like the modern Amplitrex tester which tests at full power gives a better picture).
Speaking very generally, many varieties of vintage tubes tend to have a longer life than modern tubes. Given the high cost of many of the more desirable vintage tubes, the decision on whether to go that route comes down to how much one likes the particular sound of a tube, how much one can budget on replacing tube, how averse to "gambling" on disappointing one is and how hard is your equipment on the tube. On the last point, some gear run tubes conservatively and certain tubes will last seemingly forever when not driven hard. With that kind of gear, it makes more sense to splurge on the good stuff. I have an amp that runs four 348s and four 349s, both of which I can find substitute tube types that cost a tiny fraction of the price of these tubes, but, I don't use the cheaper alternatives because the amp has been running for years with the same tubes (which were probably old when I got the amp).
Speaking very generally, many varieties of vintage tubes tend to have a longer life than modern tubes. Given the high cost of many of the more desirable vintage tubes, the decision on whether to go that route comes down to how much one likes the particular sound of a tube, how much one can budget on replacing tube, how averse to "gambling" on disappointing one is and how hard is your equipment on the tube. On the last point, some gear run tubes conservatively and certain tubes will last seemingly forever when not driven hard. With that kind of gear, it makes more sense to splurge on the good stuff. I have an amp that runs four 348s and four 349s, both of which I can find substitute tube types that cost a tiny fraction of the price of these tubes, but, I don't use the cheaper alternatives because the amp has been running for years with the same tubes (which were probably old when I got the amp).