It's not just preference. Resolution and ppi also play a role.
Resolution and PPI are two sides of the same coin. And while important, do not a great smartphone display make on their own.
That being said, it's pretty widely known and cited Samsung has pretty much worked out all the deficiencies of AMOLED in the Note 4. Things that used to be an issue like brightness, oversaturation, too much contrast, poor color reproduction are not present in the Note 4's AMOLED.
That being said, their representation of the PPI in the Note 4 is a bit misleading as they utilize a pentile matrix of pixels and subpixels in which there are the same number of blue and red pixels (515 per inch) but less green pixels.
Whereas the iPhone 6+'s iPS LCD has the same number of green, red and blue (401 per inch).
In the end though, these numbers aren't what matter. What matters most is how the display looks to the user. And both displays are fantastic and second to none. They truly are at the top of the list, no matter who edges out who.