Ok the pros of the iPhone 6+ is the smaller width, depth and weight. It might be taller but that's not something that will affect how you hold the phone unless you place your fingers on the top and bottom of the phone.
The camera and its functions seems to be better as well on the iPhone 6+. The slow-motion, time-lapse and cinematic functions are pretty cool.
Build quality, all metal compared to Note with its plastic back.
The iPhone 6+ has a 1080p screen which will require less power and battery to handle than a QHD screen, seriously QHD is just overkill! 720p resolution on my old Note 2 was fine. The QHD display will only make the Note 4 slower. The white colors on the iPhone's LCD screen will also be pure white compared to yellow/green/pink/blue whites on the amoled screen of the Note 4.
The biggest pro in my opinion for iPhone 6+ is iOS. Nicer looking and just a smoother experience. Touchwiz is a lagging hell and the bloatware on Samsung phones are just awful, you could root it but it's pretty risky. I wouldn't do it to a new 700 euro phone. Plus it requires some technical skills most people don't have.
However, the Note 4 is cheaper, has upgradable storage with up to 128gb sd cards and has a S-Pen which comes in handy sometimes. The amoled screen is gorgeous with vibrant colors and black colors being completely black/turned off. Amoled screens don't seem to have light bleeding, I haven't seen one with it compared to LCD which it's very common (returned my iPad Air for this reason). Only downside of the amoled screen are some pretty nasty viewing angles with white colors not being pure white as I've mentioned. There is also the risk of the mura effect with a faint grid like pattern/lines visible on the entire screen, google search "mura effect amoled". All my amoled devices had that issue.