The biggest benefit of starting in Latin America is the cost of living ... I worked for 2 years without a salary because rent was like $200/month for a house. Downside is that makes building an unsustainable business easier as well heh.
Disadvantages can include poor infrastructure, in Nicaragua I used to get elec/water/internet outages each week for hours at a time. It's also a very hot part of the world although I'm Australian so that doesn't phase me much.
Language and culture can be barriers in subtle ways, it's hard to surround yourself with like-minded people outside of the internet and this will be especially true the further you get from Guatamala City. The distance from your market may or may not be a problem as thesingularity mentioned, I don't think it matters that much for most of the time plus you can fly up to SF or anywhere else pretty cheap.
You will have trouble hiring sales/marketing/bizdev guys with a global worldview but that may not be a problem for today.