Very good post!Since no one mentioned it, I want to add that M.2 comes in a couple of flavors. NVME and SATA. Many of today's current motherboards can accept both, as long as the module is Type M or Type B+M. For example, ASUS lists this in the M.2 description as "SATA & PCIE 3.0 x 4 mode" for the ROG Strix B550.
Unless your motherboard is keyed to only accept a SATA type M.2, always go for the NVME version or you will be limiting your speed to that of SATA. SATA theoretical speed tops out at 550MB/s or 600 MB/s, depending on who you ask. The prices between SATA and NVME M.2 consumer grade modules are nearly identical, so keep an eye on the description and make sure you purchase the correct one.
For example, on Newegg.com:
Western Digital WD Blue SN550 NVMe M.2 2280 1TB is $94.99
WD Blue 3D NAND 1TB Internal SSD - SATA III 6Gb/s M.2 2280 is $99.99
They are both M.2 and they look the same (except for the keyed slot), but they are very different animals. You probably won't notice a big speed difference between the two in actual real world use, but why limit yourself?
And as usual: at least do a quick research for everything important that you buy.
10 seconds and you'll see the data rates of the nvme's blowing the sata ones out of the water
