Daniel Bader writing for iMore:

It’s not easy to tell which device wins this contest, as both the iPhone 6s Plus and Galaxy S7 dominate a couple of categories. The iPhone’s strengths are in situations with ample light, particularly with the sun as a source; Apple manages to capture photos with more natural colors and less artificial sharpening. This is especially evident in shots with lots of minute detail, or in macros.

The Galaxy S7, on the other hand, performs well in lower light, owing to a larger sensor and wider aperture. That said, the device doesn’t outright dominate, as photos taken in dim situations tend to emerge warmer and less lifelike.

I hope I get a review unit to test this out personally, but it appears from the samples Daniel posted, that the iPhone takes the more naturally pleasing and technically better photos, while the Galaxy S7 prefers to go for more ‘pop’ (eg. in HDR mode). Having said that, many users prefer the latter, just like they like the screen’s colours to be unnaturally saturated.