Got the KnowRoaming sticker a few weeks ago. Have already used it in U.S., Bermuda, Colombia, Panama, Ecuador and Peru. Latin America has great connectivity in the cities and the packages are well worth it. I have a VoIP service app for my US number and it works perfectly over the 3G service I get with KnowRoaming so I haven't used the call function yet. I've had no big problems switching between countries; sometimes I have to reset the phone, but no big deal. Sometimes I have to reset KnowRoamingTraveleSIMs before the package starts working and it always takes a few cents off my load so I can log in and activate the package; that doesn't seem very fair haha.. Otherwise, this is one of the best inventions I've seen for someone like me who travels constantly. Yes, $8 a day is a little much in some of the countries, but for no hassle/no registration/finding a mobile phone shop in every country, it simply can't be beat and is well worth it; also cheaper than most or all of the "Global Sim Cards" out there. I still have one for the few countries KnowRoaming doesn't support, but this is my go-to from now on. Bravo.