I found a couple of errant bags of Stash Premium Green, permitting the propitious possibility of a steep-off with Harney & Sons Japanese Sencha (see below for the openers to this steep-off).
Now for the true test: the scent and the taste!
I find that the brewed Stash Premium Green has a stronger, richer aroma, with a slightly cerealesque facet to it, while the Harney & Sons smells lighter and more vegetal.
Perhaps unsurprisingly, the taste, too, differs in that same regard. In fact, now that I sniff and sip these two green teas side by side, I am realizing that the Stash Premium Green lies just over the sencha line, veering toward the genmaicha side. I have always loved this tea, and I do affirm today that I could easily imbibe another 1000 bags!
Perhaps, though, I am comparing apples and oranges. It now seems pretty clear that Stash Premium Green is not a blend only of senchas, which the Harney & Sons Japanese Sencha certainly is.
I like them both. I really do, but the golden Stash brew strikes me as more substantial, with a more pronounced flavor and a richer texture than the brighter green Harney & Sons brew. This despite the fact that the spent Stash bag weighs about half as much as the spent Harney & Sons bag!
I guess that all of this goes to show:
on ne sait jamais!