Now that you mention it, there is just one phone that could beat all Lumias at lowlight, it would be the Xperia Z2.
Xperia Z2 has a f2.0 aperture coupled with a decent sensor size and can go upto ISO 6400, compared to ISO 4000(which is max of Lumia).
However Sony follows a 6 month phone release cycle, which is something I very much despise.
Moto X and Nexus 5 we're supposed to be high-end devices priced at mid-range prices, so sacrifices had to be made.
Lumia still manages to outperform most Android phone cameras out there, especially if mounted on a tripod.
Anyways we are going off-topic, what are your thoughts on Windows Phone 8.1?
I really liked the WP 8.1, integrations taken, I believe it was for the best.
Now developers have the freedom to integrate the People Hub, Photos Hub.
The problem is that the Facebook app is not good ...
Test the app VK (social network widely used in Russia), the integration works perfectly.
I imagine to see Instagram or 6tag integrated, or even WhatsApp.
What does not really like, are the new native apps bad ( Calendar takes to open). Well, no need to mention the Xbox and Xbox Music Video (is possible to put a subtitle? None format I tried worked, I believe is only for online videos at Xbox Video service).
And the fact that the email app is very simple (but fast). The Windows 8 app is much better.
In fact, why not make these universal apps?