I have a ton of 12AX7, 12AT7, and 6SN7 vintage tubes, both military, “commercial,” e.g., FAA contract tubes, and regular consumer grade. Military tubes are more rugged with more micas, support rods, etc. I don’t think military grade sound better per-se, rather I think they were simply manufactured at the hight of US tube production expertise from early 1940’s into the 1950’s and 60’s. Once the transistor came into the picture, emphasis on tube production declined rapidly and quality suffered.
That being said, my absolute favorite 6SN7s are a pair of 1945 JAN Sylvania 6SN7W and 1950’s Tung Sol 6SN7 GTWA. My favorite 12AX7 is a black plate Raytheon from 1950’s with Baldwin label. I have an identical back up Raytheon with the JAN anchor on it. They sound the same, no difference.
if you can find a high testing RCA black plates from same era, factory, etc, a consumer branded will be the same tube, same construction, same sound characteristics. RCA Command were just pulled and labeled as such because they tested higher with closer matching tolerances, so I’ve read.
Buy two or three, don’t do like I did and go crazy buying and collecting hundreds of tubes that will outlive you and your children! Can’t listen to them all enough to wear them out.