See here .
I guess noone raises any doubt on the quality of the porting;
but rather the disappointment to not have the NOKIA label on that phone.

Talking about battery life:
I have IP7 as work phone ans SFx in my pocket also ,

If not used IP is superior , like for weekends .
If really used I can use IP' s battery in one day and in bad coverage areas , IP is eating battery like wolf. I was some weeks ago travelling by train , usef SFx for internet and IP7 for calls ( work) in the evening both almost died. And after all I used SFx for net maybe 4h and IP7 for talk one hour during day.
The problem is power saving , but if really used like bullzoser , I would not like to pay for IP7 my self.

Here we can see the differences between fake Nokia 3310 (2017) and original (HMD made) Nokia 3310 (2017)

https://www.youtube.com/watch?v=sl1t16o5-4E

There is a difference between resource hungry and suboptimal power management.
Granted, it makes no difference why sailfish drains same hardware faster, but my guess is there is room for improvement in driver usage etc.
The bottleneck is engineer power to optimize hadk imho.

Maybe in the cause, but not in the effect. In both cases you need more resources than an alternative to achieve the same result.