Got my GPD Win today. The console works, the buttons work and the Windows key works, so I'm happy with it. Bought it from Geekbuying on January 9, they shipped it on January 13 and it arrived to Argentina's customs on January 25.
Now, for anyone from Argentina thinking on buying this:
First, if you don't pay for a courier you'll have to pay the taxes (50% of the console price) and will have to get it from customs. Even if you pay for EMS delivery (I did), the "puerta a puerta" service doesn't include packages which cost more than U$D200. You'll get one telegram saying that it can be delivered to you, you'll complete all the paperwork from the AFIP website and you'll get a second telegram telling you that you have to go to customs.
At the end, the total cost was: 380 dollars for the console plus EMS shipping, 177 dollares in taxes, and 100 pesos to Correo Argentino.
If I had to buy it again I'd buy from Geekbuying with DHL shipping, of from EvilDragon with UPS. It costs more but in theory you get it delivered directly to you without paying anything else.