Some NOS are better, some are not. Know what you are buying. Many current manufactured tubes are the best ever. Sometimes mid-range bloom can be achieved with NOS tubes because of inherent problems with equipment and equipment matching. Just because a tube is NOS puts it far from a recommendation. Good luck.
Why are NOS tubes considered superior?
The idea of "tube rolling" in my ARC preamp is something that I am considering. What I'm not sure I understand is the quality of tubes manufactured today vs. older tubes. It would seem that with modern manufacturing technology new tubes would be of higher quality than tubes made in the 60's and 70's. How are the older tubes better?