While in numbers and certainly profit, Apple is going to have a great 3.5 months, I doubt their market share will change to a majority in the US and not much at all globally. The entire pie is still growing and Apple has lost share gradually for a while. This might get them back to where it was 12-18 months ago.
I think the IP6 is the much more compelling phone. The IP6 Plus does little to make me want to switch from Android phablets. I find the back a bit ugly, the larger home screens can still only house app icons, and you can't do any multitasking which I find frustrating. Having to completely exit an app to switch to another one? Might as well use a 4.7" screen.
I think Samsung is in fine shape with the Note 4 vs the IP 6 Plus. But Apple will have 6 months in the sun until the new Android flagships come out and the narrative will change yet again. I expect they will focus on increasing the already existing battery life gap with the IP6, waterproofing, 1440p screens that draw less power, OIS, and for Samsung metal frames. Then the story will be Apple is falling behind again with only a S refresh coming in 6 months and how they're going to struggle for blah blah time.
Or long story short, things will continue to flip flop with overall market share reversing from the last year but not much more.