Trying to answer:
1. You have more choice: stock android; sailfishos; lineageos; some other rom thanks to Sony open device program...
2. What's wrong with Android? Yes, it is almost dominating the mobile world, but we should be thankful to Google releasing it's source code through aosp. This makes LineageOS and other rom's possible. In fact - LineageOS is fully open source (except vendor firmware&drivers). We can't say that about SailfishOS (using the same vendor firmware&drivers through libhybris + closed bits in SailfishOS itself). We may go even further and say that SailfishOS on real hardware would not existed if there did not exist Android
3. To my experience LineageOS is very good on my Nexus 6. I have not installed any Google Apps package to it and using only open source software repository F-Droid. It has been very stable through all the weekly builds. I do not remember any need to restart it except these weekly upgrades. As of power hungriness - my December 2015 Nexus 6 lasts longer than December 2017 XperiaX at my usage pattern. Well - if with Gapps, then it could be vice-versa... As of evilness - Android is controlled by US and SailfishOS by Russia :P I do not remember a case through history that US has tried to conquer and occupy Finland (or Estonia)...
4. Best greetings to the other side of Gulf of Finland