I was in germany on a longer term, and had an o2 data packet, so 5GB prepaid for €25. Worked for me in Germany. Only.
I had family visit, and we were in four countries in a week, we did the $50 ATT package so business e-mail and Skype were accessible no matter what (roaming in the EU and CH with prepaid almost never works) plus the 150 texts pack and it simplified everything. I use a Skype number that is forwarded to by my google voice number when I'm over there.