At least it was an internal battle where maybe the Note5 stood a chance - there have been many times where I wished my iPhone had a removable battery and cheap storage options.
Now it's no contest ^_^
I haven't enjoyed iOS on phablets - unlike the normal iPhone 6. Things you do a hundred times a day bothers me - not having a back button at the bottom and having to click the top left to back out of menus - constantly drives me crazy. It's fine on the normal 6, bad on the 6 Plus. The motion to shrink the screen is a band-aid that gets tedious.
Also the lack of any functionality to actually use the big screen seemed like a waste - it really is just a bigger 6.
Now each OS will be better in some areas for sure. But at least for the apps I use (which are mostly all major company, mainstream apps), I don't find any real difference between them on my Note 4 or my wife's iPhone 6. For all the ballyhooed smoothness, I don't find any difference (though I am running a debloated ROM). And for everything iOS does do better (like Airdrop), other things drive me crazy like not being able to email videos I just took on the iPhone in anything but crappy quality.
I do think $700 for the Note 5 32GB is going to be competitive vs. the $750 for the 16GB iPhone 6 Plus. And $770 vs $850 for the 64GB versions. Notwithstanding I'm sure there will be at least a $100 promo for the Note - whether it be Neflix or trade-in deals.
Even with the 6S Plus, they will be equal in build, screens, performance (awfully diminishing returns here BTW), biometrics, and camera.
The Note will give you s-pen (I do like the new writing on the screen when screen is off feature), faster charging, fast wireless charging, have a significantly better screen to body ratio and probably be easier to carry (narrower, curved back).
If you love iOS, I'm not sure why the Note would have pulled you away - expandable storage is just a difference in money since you could get a 128GB version iPhone and the Note 5 is still going to be cheaper.