Here's my TL;DR version/guide regarding which NVMe to buy for a macOS boot drive. Use Amazon or Newegg.
1. Have an older PCIe 3.0 board ? Plan to keep it longer term ? Get the SN570 in the 1 or 2TB size.
2. Have a PCIe 4.0 board like the Z690 line ? Go with SN750/770 or the higher end SN850(X).
Newegg doesn’t have any WD Green models beyond the SN350. Is that a good choice or go higher up the food chain?
Green drives from WD refer back to the days when they only sold 3.5" spinning platter HDDs. Don't even look at that line for NVMe. Your #1 choice should be from the WD Black line. Especially this weekend as they are on sale.
The only WD black you'll
need to avoid is the
SN750 SE
These do not use the more desirable proprietary WD controller and won't work as well.
The best bang for your buck is the SN770 1TB drive for $79.99 at Newegg or Amazon.
If you need 2TB that should even cost less per GB of storage. The SN850X looks like a
great deal in the 2TB size this weekend. On Newegg it's already on back order at the
$170 price.
For those that want to go super low on cost, the WD SN570 drives are the best choice.
If you just need a smallish 250GB macOS boot drive. $30 gets you in the door for an upgrade.
For those with an older PCIe 3.0 board, you'll still get fast boot times and not be able to
notice much speed difference compared to the higher end black drives. Write speeds are
significantly lower on the WD Blue line of NVMe drives. On a tight budget, yet still need
a 2TB NVMe for storage ? The WD Blue SN570 2TB is the lowest price per GB on Amazon.
7 cents per GB for a quality name brand NVMe drive is about the best deal today.
Here's the speeds you could expect to get with a 1TB or larger SN570 Blue drive.