Fairly certain they both have IP block making them only for their respective countries, so find out which one doesn't IP block you and go with that one.
i have a crap load of trouble registering with the Aika Global site for some reason all of my emails are unavailable. After 7 different e-mails the stupid verifications shows up blank and i can't email the damn company cause im not registered......this is getting old fast should have registered before downloading the damn game >_>