It's still way too early to tell.
Like I mentioned in a photography thread, megapixel count alone isn't a true way of judging overall camera performance. The iPhone 6 has a pretty great camera despite 'only' being 8MP. I honestly expect the 6S to be about the same, albeit with more detail.
If I had to pick, I would say Note 5. Not because of the higher MP count but due to the features it has. The iPhone has always been about simplicity in its camera app. There's barely any true manual control. Just a shutter button and an exposure slider on the focal point. The Note 5's camera app has a normal mode but also a Pro mode that gives you more control over your shots, like a DSLR. Of course, it's not on the same level as the LG G4, but it's close.
But really, wait for sample 6S shots and then we'll decide.