I bought into the 6F8G TS RPs a long time ago. Those who have both this and the 6SN7 of these say that the earlier 6F8G is a tad better as I don't have both I cannot verify this. What I do know is that the RPs from Tung Sol that I do have including the 6SL7 are head and shoulders above any other tubes in their type. I have National Union RPs as well. Yes them TS go for a lot of money but if you don't drive them hard they will last and last unlike power tubes. The 6F8G excel in every dept and they are so organic. In my Bada hybrid amps the preamp section uses 3 tubes - 1 driver and 2 o/put. I use the TS as driver and 2 Russian 1578 as o/put. This combo was many years ago the end game for me, I've never heard a tube combo anywhere near this sound. As I have quite a few of these TS I tried using 3 in the Bada amps, it is an overwhelming organic and emotional sound with acoustic music totally involving.For most music the TS/1578 is still the best. I'm still looking at different o/put tubes for the D/V. I'll bet that many would really like the Russian mil.spec 1578, like the 6F8G they are no longer cheap. Around the millenium both could be bought for pennies. If anyone does fancy trying the 1578 be very careful, there are lots of scammers trying to sell you the cheap as chips standard Russian tubes, they never show you a full on shot of the ladders - caveat emptor.