V-NAND is not in high volume yet, that of course changes some now that product is shipping, it will get even better by the time the SSD 850 EVO hits using V-NAND. Samsung is done with planar NAND for client drives anyway, V-NAND is the future, for the next few years at least. So yes, pricing is high now but should fade, like all tech does, in volume. Most people can't justify the expense for the better performing drive, the 840 EVO and MX100 are still better options for the market at large.
As for PCIe form factor SSDs, yes, they'll migrate to V-NAND too eventually and yes, they'll perform better too.