Hi An,
This is an end game amplifier IMO for both sonically and visually! 
Thank you - I'm glad it is doing exactly as intended!

I am sure Vinnie would be the best man who could inform us the differences between these two 300B tubes since the designer has listened with these tubes numerous of times in the L2i SE Integrated. For me the Takatsuki and Elrog have totally different sounding characteristics and both are quite unique at this caliber. The Tak has the best possible level of transparency with more intimate feeling while the Elrog is just a little warmer and has more weights in the whole presentation...Different listeners will appreciate differently between the two tubes...system synergy is a must!
Hi An and Jason,
I agree with An. The TAK TA-300B is the most transparent of the DHT's that I've used in the L2 Preamp / L2i-SE. It unravels all the fine nuances in the music with remarkable speed and clarity. I wouldn't call it a "warm" sounding tube (although it is never bright, or boring / sterile sounding).
I find the Elrog 300B to be warmer overall, and a bit more laid-back in how they handle transients in the music. The bass is more weighty (but still not a strong in the bass as something like a KR PX-4).
I believe the gain with the Elrog 300B is around 2dB lower as well. In a brighter and/or leaner sounding system, the Elrog 300B would probably be preferred over the TAK TA300B.
As An mentioned above, the "best" triode really comes down to system synergy.
Some of my favorites (in no particular order) have been:
Western Electric WE-300B
Takutsuki TA-300B
KR Audio T-100 (similar sounding to the PX4, but more top-end extension and openness)
Some of my "second favorites" have been:
Elrog 300B
KR PX4
Svetlana SV811-10 (specifically when I want warmer, richer, and bass-heavier sound with rock, or with bright and poorly mastered recordings)
Vinnie