I fully agree with your original post that the Steddi Go is very closely identical to the SVTDI, and so did Nathan in this post :Steddi, Go! - simple tube D.I.I saw an old post of mine being quoted above. I corrected myself a little later with this follow-up:
Just look at post #5 on that page and Nathan agrees it is like the SVTDI.
But I guess Nathan who designed and made the Steddi Di, you, me and many others are completely wrong and "74hz" who loves to crap on anything Sushi box or C2CE must be correct, at least in his delusional mind.