Let me start by saying the picture of YOUR GG is sublime. Real Dac envy, and I LOVE the look of my B7, but the GG is that much more of a looker. The first GG in Holand had a provisional casing that was not as good as yours (and will be replaced with the production version you have).
Then, as to whether the GG is better, that can only be answered starting now, as NO GG was old enuff to be broken in and thus compared to the months old B7s all around the world. Hell, even Lukasz cant keep them long enough to know. What I do know is that it's the same circuit, but with Gucci parts and better chassis (tastefully implemented copper with great EMI shielding), so the improvements should show up in time. The parts upgrade alone will ensure that, plus the copper case…its a slam dung. Whether its that much better in SQ to justify the price increase is the eternal question, but just based on looks, supplied stock tubes and default DSD256…I would say YES to those who can afford it…especially those with Kondo gear!
Yes, I know that the PCM would grow on you, as it takes longer to break in. If the DSD also improves on break-in, it will be scary. Just wait till you get the Regen, you may need Pampers. LoL
I am not even sure that USB cable differences will matter that much, though it still may.
Finally, I am not sure what your fav tube set will be, but you are ceertainly playing in the right neighborhood. Those you are getting and what you already have are already forum favourites and I trust you read the diatribe from Greg at ACircle…he has written some great reviews ion tubes there, plus he created a Facebook page called Lampizator Big 7 tube rollers group with even more feedback:
https://www.facebook.com/pages/LampizatOr-BIG-7-tube-rollers-group/1527145964228079
AL and SFox also made lots of evaluations of tubes at ACircle and when I spoke with AL today, his endgame is now a Golden Gate HeadDac! Again, he wants to be the pioneer there.