I tried both forwarding calls through Google Voice and using Google Hangouts over wifi. Haven't used Google Fi but haven't exactly heard good things from friends.
Has anyone had recent good experiences lately?
My primary number is a Google Voice number, so almost all calls for me are done via data. I don't use it very frequently away from WiFi but when I do the service is fine, and my bill is always pretty low (my usage varies wildly between $30 and $60). I'm a happy customer, though other carrier's unlimited plans have been enticing lately. I'm holding out hope that Project Fi drops their prices the future to be competitive with unlimited plans.
Also, their Project Fi support is great. They replaced my Nexus 5X (bootloop issue) without any hassle (just a 3 minute chat session) and then they replaced it's replacement (charging port was smoking and melted within the last week—yikes) outside of warranty with little hassle (just a longer chat session). Both times, I had the replacement less than 36 hours later.