Nirvana use to be ok a long time ago; but my last experience with it, will the Northern Lights x Big Bud didn't actually grow buds. The biggest most vigorous plant with big leaves, but it refused to grow buds. I gave it a good chance, left them there until the rest were halfway through flowering, but still not buds appeared.
And the other ones, they seemed quite weak and feeble plants.
I don't think Nirvana actually breeds seeds themselves, I think they are just a company who buys seeds off closet pollen chuckers and sells them under their label.
I would say go for KC Brains; comparable prices and at least there is a face to the company, not like anonymous Nirvana.
That's certainly contrary to my own experience. Of the several strains I've grown over the last 3 years their royal flush is my favorite so far. It's why I'm now growing one of the parent strains, Eldorado, & why I may grow the other, Jock Horror.
The rest of what you offer is derogatory speculation.