I don't know that any of them are more reliable than any other. What does probably vary is the level of screening/testing that happens between the production line and you. I tend to like Tung Sol and Mullard tubes in various preamp positions (still a JJ for the cathode follower and either a Sovtek LP or EI Yugo for the PI). Given the option though, I'll buy the GT or TAD-branded versions, or buy through one of a variety of radio supply-type shops who do more extensive testing.
I do think NOS tubes were constructed a bit better. The higher volumes being made gave them margins that allowed greater precision and care during production. Honestly though, I don't think they were THAT much better off the line, it's more so that manufacturers back then could afford to discard tubes that weren't up to spec.
