I installed a LineageOS build from the time of @ronaldteune’s writing recently. Encryption ended in a bootloop and needed to be fixed the hard way, FM radio didn’t work. Perhaps that’s what he meant ;-), and I didn’t look any further for other issues.
A LineageOS build from July fixed both issues, since then I dropped Fairphone Open OS myself and switched to LineageOS.
Dual SIM might still be a bit of a concern as you know yourself.
I didn’t count the bugs, but for me personally LineageOS immediately felt a bit better on the phone than Fairphone Open OS. I don’t know what part the step from Android 6 to Android 7 plays in that. I guess comparing an Android 6 OS to an Android 7 OS in that regard may be a bit unfair.
Just for reference:
In LineageOS battery percentage in the status bar is an option you can turn on (in Fairphone Open OS you have to install an App that just turns this option on because it is hidden).
In LineageOS all available reboot options are in the reboot menu, you can even add screenshot to that via Settings.
And then for me the compass works better. I had no real problem with calibrating it when I needed it before, but this was a really positive surprise for me because I didn’t think it was a software thing.
This is probably not going to happen as long as there is no official support for Android 7 on the Snapdragon 801 SoC of the Fairphone 2. And if in doubt they probably would continue Fairphone Open OS on an Android 7 base then.
Any community Android 7 port can work as brilliantly as it wants. Fairphone as a company need official support and they still have that with Android 6. Only when Google doesn’t do security updates for Android 6 any longer and Fairphone don’t get support for Android 7 turning to community ports may become an option for Fairphone. They are a company, official procedures matter.