I've been a Google Fi user since the dawn of the service. I still use my original Pixel but over time added a few "data only" SIM's to the service. The more devices I add to Fi, the lower my overall mobile services bills have gotten. With the news that's leaking out, if true, finally Fi will add official support for iPhone and other devices including the OnePlus 6T and Samsung smartphones.
Many would say it's about time, as this means SMS and calling comes to devices previously only able to use data services. My love for the service revolves not only around the low cost pricing, but just how elegant it really works.
On my Pixel, I can switch, or allow auto-switching between T-Mobile, Sprint or Cellular One, while in the UK and EU I can operate on Three/UK and of course operate on Wi-Fi. Combined with Boingo the service let's me operate super efficiently while only being charged a base rate of $20 a month and a PAYG (Pay As You Go) data plan. Last month my Fi bill after a few more days than three weeks in Europe with the Pixel, an iPhone SE and an iPad was $33.00, mostly on the Pixel. I also used a local Orange SIM which I spent 35 Euros for an iPhone 7 on and another 15 on an iPad SIM also on Orange. This was the least I've paid on any trip in the last three years, as costs for data plans in Europe are dropping, better Wi-Fi has arrived and hotels, restaurants and airports have all made the process of jumping onto Wi-Fi much easier, more multi-lingual, and less restrictive.
One of the things I do is link my Echo Tap to the Pixel and that keeps all of my Alexa services right where I need them. That avoids having to tether the Echo to each and every hotel as I travel from hotel to hotel or a friend's winery where I'll stay often. If I'm somewhere that Wi-Fi is sketchy, the hotspot feature of Fi is a lifesaver as not all PAYG SIM's let you tether depending on carrier and country.
What I do with my iPhones and iPad, is pull the T-Mobile SIMs out and pop in the Fi data SIMs and between Dialpad, Telzio, Google Voice, Telegram, WhatsApp, Facebook Messenger and Skype none of my usual communications are disrupted, and because a data SIM from Fi has a real phone number iMessage still works on the iPad, but not on the iPhone, something the updated service should change.
The reason Fi is so valuable, and it may be their secret sauce is just like a local SIM from Orange, Vodafone, Telefonica/Movistar, EE or any in country mobile operator, is how the network is architected. Much like Truphone has done with their global network, Google does what none of USA mobile operator do. They keep your data traffic local to the closet POP you hit. This is much like the way the old Blackberry network was working more than ten years ago, and why messages and email were so fast back then and with Fi are too today. In essence, your data is on Google's network most of the time, and if you're a GSuite or user of any Google service, everything is just faster.
Basically because Google operates a network globally that interconnects with almost every major carrier and service provider, as does Facebook and to some extent, AWS, your sessions are usually never more than three hops to the service you need. This is why email moves faster, but more importantly why services like Hangouts, UberConference, Zoom, GoToMeeting, WebEx all work better. Instead of the session having to be hauled all the way back to your USA mobile operators home network, and then back, you jump on quickly with lower delay, less jitter and far less latency. Conference calls, being the core way I communicate with scheduled calls using the apps on the devices.
Services, especially VoIP providers who network their signalling to go to the closest POP for traffic routing and who do the same with the media path provide better service. Dialpad for example uses the Google Cloud to manage the signaling and interaction with Gmail, Google Calendar, Contacts, LinkedIn while having 7 or 8 global data centers that handle the media path, which is why when I'm in the USA or anywhere in the world, a data mobile broadband based HD call or logged into UberConference over the mobile app sounds like I'm right next door which is why Fi is such a hidden gem in the world of mobile connectivity.
I'll admit, that as a USA only service, Fi is good for you if you spend lots of time connected to Wi-Fi, much like Republic Wireless does. But for a global traveler, global nomad or anyone who crosses borders regularly, it can't be beat for functionality as much as it saves you in money.