See the MPG review of the OWC Accelsior Pro Q PCIe SSD.
Operation has been rock solid, and strange in a sort of way: I just don’t notice that there are any drives involved. That is, when I save or open in Photoshop, it’s so quick that the drive ceases to be a consideration. Ditto for any other operation.
Well, almost—Photoshop itself remains a gating factor, clearly not writing or reading optimally, even with Disable Compression for PSD/PSB files enabled. Photoshop is just not built (yet) for working with extremely fast SSDs—internal inefficiencies keep it from utilizing full drive speed.