There is little to no reason to purchase a DRAMless SSD. Not only do they (usually) perform significantly worse than a comparable SSD with DRAM, but it is often to the point where you might as well opt for a fast hard drive with a smaller, better SSD to act as a boot drive. In even a simple sustained random 4kB read, the MX500 easily outperforms the Mushkin Source, which is the fasted dramless SSD AnandTech had tested at the time. It's worth noting you could get similar performance to this MX500 for a lower price, such as from a two-tone Blue/White WD Blue m.2 SSD, a TeamGroup Vulcan, or a Sabrent Rocket SSD depending on costs at any given time.
NAND flash types
In general: SLC > MLC > TLC > QLC.
One should avoid buying a QLC drive in most instances, as QLC has the worst endurance as well as the worst overall speeds. You'll often see high capacity QLC drives cheaper than an MLC or TLC drive of the same capacity for this reason. QLC drives often don't come with DRAM since QLC drives tend to be budget-oriented, so it's important to look out for that. There are however exceptions to this statement such as with the Rocket Q thanks to a good controller, good 4D chess caching, and second generation QLC. AnandTech review available here for the Rocket Q.
The NVMe M.2 vs 2.5" SATA debate
This is not really even a debate. Even if you want to spend easily $400+ on a top of the line SSD, assuming you are the average consumer, the reasonable performance difference one is going to see for almost any task, be it game load times, moving files around on your pc every once in a while, or even just booting windows is going to be negligible. If you have a use case for a drive that you KNOW (not think) can utilize sustaine 5GB/s sequential reads, go right ahead. However, for most people, you will likely have pretty much the same experience on a $400 Samsung NVMe drive as on a $100 2.5" SATA WD Blue SSD.
Should you get a SATA M.2 SSD?
It is worth noting that not all systems support SATA M.2 drives, so this could be a problem. More and more often, laptops are omitting the hardware required to support SATA M.2 drives. While it is not completely gone, it is likely to fall into obscurity in just a few short years. If you do not want to have to deal with adapters, going with an NVMe SSD that provides good performance at a fair price would be your best bet.
|SSD||Price||Form Factor||Connector||PCIe Gen||Controller||Cache||Cell level||Additional Notes:|
|WD SN550||M.2||NVMe 1.4||3.0 x4||SanDisk 20-82-01008-A1||SLC Cache, DRAMless||TLC||In spite of the lack of a DRAM cache, the SN550 well outperforms other SSDs in its price bracket|
|WD SN750||M.2||NVMe 1.3||3.0 x4||In-house controller||SK Hynix DDR4||TLC|
|HP EX920||M.2||NVMe 1.3||3.0 x4||SM2262||Nanya DDR3 DRAM Cache||TLC|
|HP EX950||M.2||NVMe 1.3||3.0 x4||SM2262EN||Nanya / Micron DDR3 DRAM Cache||TLC|
|SK Hynix Gold P31||M.2||NVMe 1.3||3.0 x4||SK Hynix Cepheus||SK Hynix LPDDR4-4266||TLC||Highly recommended for all builds, especially laptops|
|Rocket Q||M.2||NVMe 1.3||3.0 x4||Phison E12S||Both DDR3 and DDR4 reported||QLC|
|Samsung 970 Evo Plus||M.2||NVMe 1.3||3.0 x4||Samsung Phoenix||512MB-2GB LPDDR4 DRAM Cache||MLC||Only recommended in very high end systems with money to burn or prosumer systems which REALLY need fast storage|
|Firecuda 520||M.2||NVMe 1.3||4.0 x4||Phison E16||Nanya DDR4 DRAM Cache||TLC|
|Crucial MX500||2.5"||SATA 3||N/A||SM2258||DRAM Cache||TLC|
|TeamGroup T-Force Vulcan||2.5"||SATA 3||N/A||SM2258G||DRAM Cache (DDR4?)||TLC|
|TeamGroup L5 Lite||2.5"||SATA 3||N/A||SM2258||DRAM Cache||TLC|
|TCSunbow X3||2.5"||SATA 3||N/A||SM2258G (reports of SM2258XT)||DRAM Cache||TLC||Good as a dirt cheap option, sold by Amazon, but has no manufacturer warranty; you rely on Amazon's warranty|
|Samsung 860 Evo||2.5"||SATA 3||N/A||Samsung MJX||312MB-4GB LPDDR4 DRAM Cache||TLC|
As of late 2020, the ADATA SX8200 Pro is no longer found to be suggestable due to a swapping of the SSD's controller and the NAND flash becoming a lottery. This is a good example of a company making a good product, that product getting a good reputation, and then said company pulling a bait & switch without a majority of the population noticing until later on.