So to clarify the OP's question.....the best way to send international would be EMS? I always thought that there wasn't a way to track it once it left the US since the other countries are not on the same computer system as the USPS does. At least that was what I was told at my post office. I always ended up sending FEDEX so that I can track it. FEDEX and UPS does cost a fortune but I am lucky to get 75% off with FEDEX through my brother.
I have shipped to Spain using USPS EMS and I was able to track the package up to the time and date when it entered customs. After that, it was in the hands of the country's mail service, and my buyer notified me when the package arrived. It did take two weeks, but that's because customs moves super slowly in Spain.