What is the best 6SN7 driver tube?


I was told by some very experienced tube nuts that the best 6SN7 is the earliest version of Sylvania VT-231. Is there any truth in it? I thought the RCA red base 5692 is the ultimate driver tube around. Any thought on this issue will be helpful.
edle
A wealth of info here: (http://www.dehavillandhifi.com/6sn7_vt.htm). I found their results very accurate, having tried the top 10 favorites of the survey in my Cary monoblocks. The 1940's, bottom gettered Sylvania VT-231/6SN7GT, is a VERY nice(transparent) tube. The tall bottle, 6SN7W has more bass slam and a deeper sound stage.
I recently picked up some Sylvania three hole 6SN7T's from Dave Hollander. I'm using them in a pair of Octave Audio Amps. The tubes supplied by the manufacturer had no markings. So, I'm not sure what I replaced but the difference surprised me. 

The Sylvania's three hole tubes produced a much better layered soundstage. I also was heard sounds at the rear of the stage more clearly. Previously these were masked. Finally, the transparency had increased from the front to the rear of the stage. Overall, the differences were not subtle and surpassed those of the supplied tubes and some Tung-Sols that I tried. I highly recommend that you give the Sylvannas a try. 

@bigbear: which 3-hole Sylvanias exactly we're talking here, Big Boys, chrome dome GTAs? Can You point to an exact example? Thx.
Sylvania 6sn7GT, 3-hole, bottom getter "bad boys" are a step up from the GTA chrome domes.  I know people like to recommend Ken-rad dark glass but fail to mention non-microphonic ones are very hard to find.  Early RCA 6sn7GT are quite nice too.  Since Russia is in the news so much lately, how about the Melz 1578, black plates with round holes? Some say they are the best sounding 6sn7 ever made, certainly the best out of USSR.  I like them.