When Google Fi first launched it could switch between two networks depending on signal quality, T-Mobile and Sprint. But then T-Mobile bought Sprint, so there was no more switching. It'll be nice to have the switching feature again. I still frequently run into areas where T-Mobile data service does not work at all (both in populated and rural areas, and often despite 4 or 5 bars of signal).

The new network is clearly either AT&T or Verizon, but apparently the terms of Google's agreement with them don't allow Google to tell us which it is. Silly, but people will find out very soon.

Google's current agreement with T-Mobile gives Fi subscribers the same quality of service as direct T-Mobile subscribers. It'll be interesting to see if that continues and extends to the new network as well.