LordConrad :
Planar TLC NAND under 20nm is crap. Under 20nm, only 3D NAND should be used.
It's a budget option for sure, but looking at the numbers that drive pushes out it's a pretty compelling product. PCPartpicker at the moment has this drive for $240 (less than 25c/GB), compared to $310 for the 1TB 850 EVO. I'd save the $70 on the X400 myself.
I still want cheaper SSDs, particularly a cheap 2TB SSD so I can ditch mechanical storage altogether, and the price isn't there yet for me. 3D NAND is obviously superior, but it's still quite a bit more expensive too. I think it's positive that we're seeing planar TLC drives that actually perform decently, unlike the trashy BX200 and similar drives we saw a while back which just make too many sacrifices to be a viable option IMHO.