Nothing. He's talking out of his butt.
Ifhe likesthe SPS stock thenhe should like the XCR stock since they are the same thing with rubber grips added to it. Same "sleek look".
The added expense to the XCR is because they are stainless steel to begin withthen nickle plated and then coated in another anti corossion chemical/ process. If you can get an XCR to rust (except for the bore)then you are really abusing your firearm.