I am staying on US, eventhough I live in EU. What good does good ping, when you don't have anyone to play with. Also this is not a competitive game, doesn't make any difference(at least not for me), if i have current 140 ping or 80 ping on potential EU server. Gathering still works the same, crafting still works the same, in combat I also didn't spot any lag. There were some hickups during beta, but I don't think those were ping issues, just bad optimization in servers software.