Edit 2016-03-26: CM13 now has a snapshot build. I started having issues with nightlies (slowness, crashes), so I backed up apps with Titanium Backup and reformatted, and installed the new snapshot. When choosing the OpenGapps archive, either go with Super or Aroma, as they both have the ProjectFi and Google Connectivity Services APKs. I’m finding that Google Connectivity Services is working flawlessly.
So, I recently jumped ship from Republic Wireless to Project Fi. I totally needed a phone that was faster, cheaper, and more reliable than my old Moto G. I decided to jump at the $249.99 Nexus 6 on Amazon and sign up. The SIM card arrived several later than the phone, so I had time to get it setup and customized to my liking. The first thing I did was install TWRP so I could make backups and install custom software. Unfortunately Android 6.0.1 Marshmallow wasn’t easily rootable, and required something called systemless root, which was in beta. After looking at the requirements for Xposed Framework installation, I opted to do a little research into running CM13.
After searching r/ProjectFi I found out that the newest nighties were working with Fi. Oh happy day! I quickly downloaded CM13, OpenGapps, and the Project Fi APK and I was off. I installed the system easily (because I have an unlocked phone with TWRP), installed OpenGapps, and rebooted. I then installed the Project Fi app (without running it).
Last night I got my SIM card in the mail. I inserted it, and went into the Project Fi app for activation. I signed in to my Google account and it failed the first activation. Tried again and it went through. It wasn’t a complicated installation, and I must say that from what I can tell it’s working perfectly. Calls come in over Wifi. Network switching is working, which I know because of Signal Spy. I must say that I’ve never been happier with a phone purchase, and thus far I’m extremely satisfied with performance of both the phone and the service.
In the future I cannot wait for more phones to have Project Fi capability. The Nexus 6 is too big for my taste (I’ve always been the happiest with my HTC One m7) but it’s working amazingly well. It was just the best bang for the buck so I jumped at it, and I’m happy I did.