I hope Project Fi has a side effect of improving existing Google Voice / Hangouts integration. While it's been slowly getting better, some of my texts sent via GV in Hangouts never get delivered, some arrive out of order. In addition, I've been able to crash Hangouts reliably and reproducibly (in latest version, by picking a GV sms conversation, pulling up the other person's contact card (by tapping their avatar) and selecting "send hangouts message"). And we still have no group SMS integration in GV.