I used to regularly swap between a 6s+ and a note 5, but ended up with the note 5 as my main phone. You will miss things about either of them, it's very hard to commit to just one. The 6s+ was a nicer piece of hardware, just amazing to hold and fondle, but it's larger than it should be with the huge top bezel. iOS is very limiting, to even get close to what I wanted I had to jailbreak and then the phone went from being flawlessly stable to semi bugged. The Note 5 is also a very nice piece of hardware, a bit thicker but also shorter, but just not as nice feeling in the hand. Android is miles ahead of iOS in functionality but you trade off some instability, that maybe Touchwiz though and not Androids fault. My wife likes the simplicity of iOS, but whenever I pick up her phone and am faced with that random wall of icons I hand it right back to her and realize why I don't use it.
Ecosystems don't so much for me so I don't really care much. I stream all my music so it's random and fresh/new. Pictures and files go through OneDrive which is the best IMO on mobile platforms. I do miss facetime as my wife has an iPhone, but one of these days I'll have to setup another video service as there are tons of them.
Wait until you get used to the S pen, you will wonder how you lived without it. I particularly LOVE the feature on the Note 5 where as soon as you pull the pen out you can write a note. Oh and the stuff you can do with Gear VR is pretty intense.
I'm definitely first in line for a Note 6, but then again I'll probably do the same exact shuffle I always do and buy the iPhone 7, get tired of it and switch to the Note 6. I've done this the last 3 cycles and you would think I would learn.