What are the financials looking like?
I am far from an expert in this area (so someone smarter than me might correct any errors I make in terminology), but the reason I ask is because the limiting factor with SSD speed is often the SATA versus the PCIe-NVMe interface, and:
SATA is far less expensive in both drive prices and enclosure prices (enclosures can use USB-C 3.1), but the max transfer speed is around 500-550 MB/s for the highest end single-enclosure/single-drive SATA 6.0 SSDs. Many SATA-based SSDs are extremely compact, using a 2.5-inch form factor and an extremely thin body thanks to 3D NAND. For most usage, this is more than enough, because it is a nice blend of speed, reliability, capacity, and great cost efficiency. The Samsung 850 PRO is arguably the finest SATA SSD made and it uses MLC flash unlike the large bulk of consumer-grade SSDs (I am biased towards MLC SSDs, but whether consumers even need the durability/longevity/error correction of MLC over TLC, and whether 3D TLC NAND adequately addresses the shortcomings of planar TLC to a point where it can dominate the consumer market, is another topic...)
PCIe often means 3-15 times the price of the SATA SSDs and can support transfer speeds in excess of 2,500 MB/s (enclosures will have to use ThunderBolt 2 or ThunderBolt 3). A large portion of the PCIe enclosures are massive when compared to the SATA enclosures. There is a lot more selection of MLC/enterprise MLC flash here, which features enhanced durability/longevity (and, obviously, speed.)
A RAID enclosure that uses multiple SATA SSDs is often a compromise between the two. The SanDisk 900 is a RAID 0 of two SSDs using the faster USB-C 3.1 gen2 and several companies offer two-to-four+ SSD enclosures for RAID setups using Thunderbolt 2/3 (the brand I am familiar with is AKiTiO, which offers the Thunder2/3 Quad, Quad Mini, Duo.)