I live in Spain, and I've bought many times over the internet.
The big stores usually seem to prefer shipping with UPS.
When I've dealt with particulars or small companies, it's been with USPS. That means that you post it on USPS, and, once in the destination country, it's the national post who's in charge. For instance, in Spain it's Correos, in France it's La Poste...
As a receiver, I prefer UPS. They're fast, and you can track the package all the way to its destination.
With USPS, once it's crossed the US border, it's impossible, as far as I know, to know its status or its location. Once, it took up to three weeks, and I was beginning to think I had been scammed when I got the Correos white delivery slip.
I dunno about the price, but UPS are, from my experience, far better.
One more thing. In Austria, I think they have pretty high taxes, so it would be nice to understate the price of the item.
Oh, and better use a small box and bubble paper wrapping.
That's all, it's all pretty straightforward