I would be switching from android to windows for the 15xx. I currently use the original galaxy note, and it has been a pretty good phone, despite its imperfections. I've been watching windows phone with interest for some time, but it's just not been ready until recently, and now it's a hardware/capability issue that is stopping me.
To me there is only one possible android device that I would upgrade to, and that is the note 4. The reason for that is the functionality that it offers. I say that to point out what the 15xx would need to get me to switch.
It just has to be as good, both on paper and in reality. What it needs to do that is 5 of the following:
- included, integrated stylus stored inside the phone (hopefully optimized for onenote)
- iris scanner and/or voice recognition (or other very easy + reliable securing tech)
- sapphire glass
- wireless charging or integrated solar charging display
- snapdragon 805 or 64-bit processor and 3-4gb ram
- 25-30mp camera (though it must be very fast; to load the app, to focus, and to take a picture)
- water/dust proof
- thinner, lighter, better design, slimmer bezels, less bulky, and QHD
That's the bar, and anything lower I won't be satisfied with for long enough to make it worth the money. If it's not out this year though, it really ought to have all those features.
Microsoft should really just make it worth Samsung's effort to put Windows phone on a variant of the Note 4 because that phone would definitely grab some attention.