I kept the OEM but, like Bushwhacker said, it sits a little weird on top. It still protects the whole area, has a rubberized backing, and the rug material on top makes it easy to slide things in and out so I kept it.
I have 4-door with the slide out tailgate and bought the OEM liner part number VM2DZ9913042C and it did NOT fit the anchor points. Hoping they make a similar liner that would fit.