Fee Fi Fo Fum, do we smell the blood of traditional cell carreirs?

Well, I did it.  I geeked out in  major way and signed up for Google's Project Fi.

For those who aren't familiar with it, Fi is Google's foray into cell phone services.  This goes beyond a cell phone operating system, to a cell phone network of sorts.  Here's how it works:

• As the name implies, Fi uses Wi-Fi for everything wherever and whenever it can. 
• However, if there's no Wi-Fi (or it's not strong enough) it also will hop onto either Sprint's or T-Mobile's cellular network, depending on who has a stronger signal at the moment.
• Mid-call, it will swap between them as needed (though some have reported a lag in the transfer, but that seems no worse than what I've experienced going between towers with a single carrier, so I'm not too troubled, yet.)
• Data is $10/Gig, but you get a refund for unused data every month.
• International data in 120 countries is the same price as data in the US.
• International calling is $0.20/minute.
• Unlimited talk and text.
• Using your phone as a mobile hotspot is included.

Drawbacks?  Limitations?  Sure:

• It only works with a Nexus 6, 5x or 6P, because those are the only phones on the market that have all the radios for all the different carriers involved (Sprint and T-Mobile use different platforms).  The upside of this is that if you leave Fi, you can take your phone to any other carrier, no problem.
• There is a funny interaction between Google Voice and Fi, where Fi takes over for Voice.  I'm not a Google Voice customer, so I haven't dug into this.

I'll update this with other thoughts and comments as I get some experience with it. 

OK, here's the update: Fi is amazing.  Not only is the data plan reasonable, but you get amazing control of data usage.  Admittedly, some of this is phone features rather than service features, but remember that these two phones were designed and manufactured with Fi in mind, and purchased through Google, so the phone OS could have been manipulated just like any other carrier does.

• Don't want any app to use data in the background?  Turn background data off.
• Want to use a VPN/data compression service like Opera Max?  Go for it.  It will be seamless.  (I had terrible trouble doing this with other carriers.)

My soon-to-be-17-year-old daughter (who is the major bandwidth consumer in our home, 4-5Gig a month on our old carrier) just barely eeeked over the 1 Gig/month we had set up, and that was before she learned how to manage her data.  This month, she'll likely not exceed 500MB. We paid the same rate per MB for the overage as we would have if we had paid in advance.

All in all, better service at literally half the cost per month.

A-flipping-mazing.