Just curious, are these "off-brands" really full-on repacks, as in, the genuine original product simply put a different package? I have read on this forum that they are, but I have my doubts (no offense, folks).
Trader Joe's does a lot of "repacks," where they contract with major food manufacturers for popular products and slap the TJ's brand name on them. But TJ's-branded products don't taste the same, or as good, as the original product from the mfr. I assume it's because TJ's instructs the contractor to take various shortcuts to make the products cheaper so that their margins are higher. So same product, but slightly lower quality.
Morebeer sells S-23 for $0.56 per gram while the Berlin yeast is (typically) $0.37 per gram. If these are the same strain, this is a pretty big difference--big enough to make we wonder if I'd be getting the same product.
My skepticism might be off-base here, and admittedly I have not used Cellar Science or Mangrove Jack repacks, so I can't speak to how great they might be...