https://betanews.com/2019/12/10/western-digital-wd-blue-sn550-ssd/
 
Western Digital unveiled the WD Blue SN550 line of M.2 NVMe SSDs. A successor to the WD Blue SN500, the SN550 is updated with a new controller that utilizes PCI-Express 3.0 x4 (compared to just x2 on the SN500). Designed in-house by WD and SanDisk, the controller is based on the same architecture as the one that drives the WD Black SN750, but is DRAM-less, and has fewer flash channels. Speaking of which, WD deployed 96-layer 3D TLC NAND flash, and wants the drive to compete in pricing with QLC NAND-based drives such as the Crucial P1. The 250 GB variant is priced at USD $54, the 500 GB variant $65, and the 1 TB variant $99.
 
Personally I believe that 99 dollars for a 1TB M.2 is very good. 
 

Not bad but how about 2TB @ $150? lol

kougar
 
Before fast-write caches became commonplace, not having a DRAM cache on SSDs led to much higher write amplification wear in addition to the perf penalties. 

Yep..Just did a couple quick benches with Momentum Cache (Part of the Crucial Storage Executive Suite by Micron) disabled and enabled.
 
 

Hoggle
It's a good price but the $129 of the 1TB Black does seem to make the slower performance of the Blue series not worth the money saved.

Not sure if that's a permanent price, it's a steep cut from the regular Amazon price. But yes, there are lots of alternatives for 110-120 that have DRAM and are not QLC. 
 
Chopping the DRAM off only saves $5 on the cost-of-manufacture.