Standard wheels are cast aluminum, with a machine finish with clear coat. Optional wheels are forged aluminum wheels, black painted finish with bolted on beauty rings that can be converted to optional (and additional cost) beadlock rings for off road use.
The forged wheel will be a stronger wheel and I believe they are a tad heavier, but as mentioned earlier, it depends how hard off road you are going to use your Raptor. The optional beadlock rings will keep the tire basically pinched onto the rim during extreme duty use, and low airing down conditions. The last factor is cosmetic whether you want a bare aluminum look or the black look. I have found the black is easier to maintain than dealing with possible discoloring/hazing of the clear coat over the years. Hope this helps