I always refer to OmbuShop as "Spanish Shopify" - I don't know if shopify allows localized stores but there are so many payment issues in latin america they really need a solution thats targeted here...
That's where Ombu Shop has an edge. Also, Ombu Shop is based in Buenos Aires, Argentina. So we understand the challenges in our region.
Dealing with each countries local payment system is only one issue, shipping is also important.
Who knows Shopify might want to go on it's own shopping spree at some point to get into the market, like GroupOn did in Chile.