We are currently preparing to deploy our software in an non EU country. Any hints, how I can check response times from any country? Just to get a feeling when we have to use CDS and stuff...
You absolutely want to test with WebPageTest.org It's a free service by Patrick Meenan and others. Essentially it consists of dedicated Internet Explorer instances, hosted around the world, which will load your page and show you:
With Webpagetest.org you cannot test from any country, 'just' from the 20 or so locations they currently support.
If you want to know more about this field, then the book "High Performance Web Sites" by Steve Souders is the best starting point.