Yes, I think the price for GB ($10 per GB) stops at 6GB and there is no charge for any used over that, up to 15 GB after which they could throttle down the speed. The price for the account is discounted for more phones per account.
I had T-mobile before switching to Project Fi. Overall, I found reception with Fi better than T-mobile but that will depend on where you are. The costs ended up being ~$10 less/month using Fi for me (one line) on average. Any month where I wasn't traveling I would pay ~$30.
I love the Pixel series phones. Fi uses an e-Sim in the Pixel which leaves my sim card slot free for another card (handy if I'm traveling and want a cheap sim card for local phone service without roaming). I can switch between the sim and the e-sim easily. Fi does not charge extra for data roaming or international texting, but does charge for phone calls placed from outside the US.
I had T-mobile before switching to Project Fi. Overall, I found reception with Fi better than T-mobile but that will depend on where you are.
Google Fi with a "designed for Fi" phone is supposed to automatically switch between T Mobile, Sprint, and open wifi with VPN, so places where T Mobile coverage is poor, but one of the others exists should work better than T Mobile.
DH has had google fi account forever. Mostly uses it as a secondary line for travel. I use one of his four data only sims in my iPad so I think it works on IOS. I use my google voice account and make and receive calls to the iPad and forwarding my home phone works in places like Scotland England Canada peru and New Zealand. Never got a voice phone sim like DH has though.
We bought a Nexus 5x from google when we signed up for the google fi service. At the time it was the cheapest option. It is our only android. The camera on the Nexus 5x phone is pretty nice for the price.
Replies to: Does anyone have google fi cellphone service?
I love the Pixel series phones. Fi uses an e-Sim in the Pixel which leaves my sim card slot free for another card (handy if I'm traveling and want a cheap sim card for local phone service without roaming). I can switch between the sim and the e-sim easily. Fi does not charge extra for data roaming or international texting, but does charge for phone calls placed from outside the US.
Google Fi with a "designed for Fi" phone is supposed to automatically switch between T Mobile, Sprint, and open wifi with VPN, so places where T Mobile coverage is poor, but one of the others exists should work better than T Mobile.