Just to add another anecdata I used google fi for ~4 yrs and was always pretty happy with it. Recently switched to mint just for sheer price competition -- ~$20 a month for a line + 5GB data beats fi coming in at like $50-60 for the same.

fi used to be cheaper for me because I would use $20 line + $10 data. Now mint is undercutting them on both price and giving more data.