been using it for years
mostly to keep the phone bill down
it great for talking to my parents (who as you may know, still live in the Netherlands)
as long as you have an internet connection you can make phone calls (or video calls) for free
so far, i have successfully used it on 3 different continents
one thing i totally love about it is the possibility to send large high definition video files, like a 10 minute file of the kids opening Christmas presents, for example