I have both Google Voice and Google Fi. With Fi, it's not meant to be used perpetually outside of the USA. If you stay outside of the USA long enough, they'll

I have both Google Voice and Google Fi. With Fi, it's not meant to be used perpetually outside of the USA. If you stay outside of the USA long enough, they'll disable your data connection until you return to the USA, although I believe voice & SMS continue to work. The biggest problem I've had with Fi is that I destroed my phone while traveling, and I couldn't find a phone internationally with which I could activate Fi while traveling abroad. I could only associate the new phone w/ Fi once I returned to the USA. I use Google Voice as my phone for nearly everything, unless it doesn't work.