As one of the most unique, and fairly scarce, printings of the card, its clear why players want to get their hands on this version of the iconic monster
Powerful Pokmon with devastating attacks prowl the shadows: Metagross can do as much as 200 damage in one attack, Honchkrow takes advantage of your defeated Darkness Pokmon to do even more damage, and the Moonlight Pokmon Umbreon can do fearsome damage while protecting itself with its Moonlight Fang attack
Full Force Virus requires a DARK monster with less than 2000 DEF as a tribute, and allows you to look at your opponents hand and every monster they control
But for full-color proxies that look real, the math changes
Pokemon First Partner Illustration Collection Box (Series 1)
There does not seem to be any indication that any one of these cards is more rare than the other but based on early eBay prices, the Shiny/foil version of Pikachu seems most desirable