Uhm, the Android data monitor already splits between WiFi and mobile data usage.

Remember, a critical part of Google Fi is that it's supposed to automatically switch your voice and data to WiFi, and that Google has rigged partnerships such that they have lots of WiFi available for you to use.

So, if you currently use 5-10 GB/mo on one carrier, the theory is that you'll use less - possibly significantly less - on Google Fi.

That's SIGNIFICANTLY different from what you can see reported about how you manually configure the WiFi you have used today.

Except I've had to turn off that feature on my phone with Google's Fi service because public hotspots aren't necessarily reliable and can result in missed or dropped calls.

Also, there is the whole security issue of connecting to public APs automatically.

They route everything through a VPM when connecting to the public APs. So it prevents that security issue.

I've had the opposite problem, Fi will drop and black list public AP's on me if they are moderately slow or have high latencies.

That 5-10 GB number is probably only mobile data, which is the number that shows up on your bill.

Remember, a critical part of Google Fi is that it's supposed to automatically switch your voice and data to WiFi, and that Google has rigged partnerships such that they have lots of WiFi available for you to use.

So, if you currently use 5-10 GB/mo on one carrier, the theory is that you'll use less - possibly significantly less - on Google Fi.

Google Fi user here.

I don't think there is any "partnership", the "Wifi Assistant" feature just joins open wifi networks. It does do two neat things: first, it establishes a VPN tunnel through a Google controlled endpoint. Second, they seem to have a database tracking the quality of wifi networks. It won't join networks that are known to be slow, and if a network gets too slow it will automatically disconnect.

In practice though, almost every open wifi network is slow. Much slower than LTE, and certainly not something you could reasonably make a voice call over.

Overall I'm relatively happy with Fi. The service is a little better than T-Mobile (still not as good as AT&T) and the management interface is dead simple. Its what a software startup would build if they went into the cellular carrier business. And for my level of usage (3-4GB/month) the price is similar to T-Mobile.

But don't expect it to save you bandwidth.

Does international work? (Considering it's on top of T Mobile)

Yes, international data is supposed to be a flat charge (same as domestic, $10/GB) and international calling happens at what I would consider to be very reasonable rates, both to numbers in and from towers of foreign countries. Also, I believe there is unlimited international texting around the globe.

(I migrated from Verizon to Project Fi, and live close to Canada, so, consider that I am used to turning my phone off when out of the country or near the border, because of Verizon's very unreasonable rates for international calling and text.)

I don't think you can order a Project Fi account as a non-domestic resident, though.

Yes, and at the same cost per gig as domestic data.

See Fi's rate card here: https://fi.google.com/about/rates/