If we were to looks at the specs of the devices alone, it is clear that the Microsoft Lumia 950 XL is the winner here but of course, hardware alone can’t win the fight.
The Microsoft Lumia might come with better specs but the lack of apps in their app store means that people are more willing to bet on the Apple iPhone 6s Plus. At least they know that there are tons of developers that are coming out with new iOS app and that things will keep moving forward.
There is also the design of the smartphone. The Apple iPhone 6s Plus exterior upgrade might be minimal but overall, it does look better than the Microsoft Lumia 950 XL.
There is also the iOS and the Windows 10. The iOS has been around for years now while the Windows 10 is relatively new. After the Windows 8 blunder, people are even more skeptical of it.
However, all of these will not matter anymore since it does look like Microsoft might be killing off the Lumia line up. Hopefully this means that they will start focusing on the Surface Phones.