Agree that the low-light without flash looks way more natural on the G4. Sure, it's a bit green, but when comparing her face to the other pictures it looks a lot closer than the super-yellow S6, not to mention all the extra detail caught behind the subject.
I don't care about the scores. I do care about how I feel while looking at these photos. As an photographer, I still feel that the 6 plus gives a very good quality photos. (in term of colors and sharpness)
Everyone even half experienced with smartphone cameras will see just how much the S6 brightens many areas especially in every indoor scenes which leads to noise which can clearly be seen even in those downscaled comparision pictures.
While the G4 might have inaccurate colors (which I cannot really judge neither can everyone else that wasn't there) this can be adjusted to by Photoshop - the noise cannot be removed!
If you take even a little time to edit the images afterward or take proper settings beforehand you will get better results with the G4.
TLDR: The G4 cameras RAW performance is way better and produces clearer pictures in low light as in less noise = clear win. Nothing to argue about.
Especially not when you didn't even make sure that all of them are using the same settings but are using auto-settings which differ from phone to phone.
And even if you're comparing the overall performance with auto-settings taking the Software into consideration as in Point and Shot the iPhone 6 is just better due their supperior Software. I would bet my two hands that the S6 has the same difficulties with proper focusing like the S5 has and that they only improved their Software slightly even when they're using different sensors (the S5 and S6 that is).