I use the Iphone 4s (Verizon) with the 50 mb global data plan. I find that I am rarely out of wifi range for Skype, and when I am not in range I can text via Skype or email and never come close to the 50 mb. As for voice, I never use it. You can always see who is calling and opt not to pick up. International text messages cost .05 to receive and .50 to send most everywhere. The 30 bucks a month for 50mb global is the way to go. I have never had service issues even in the darkest parts of the world... Just make sure you activate the global function (cdma/gsm) on your phone. Also, texting iphone to iphone counts as data not sms. So the text cost does not apply if you have the global data.