Switching from a Windows Phone [Nokia Lumia 920] to an iPhone 6 to a Microsoft Lumia 950

Update Jan 2016: So I've been using the Microsoft Lumia 950 lately as my primary phone. I notice that for the most part I am happy with my Lumia. I return to my IPhone for a few apps - Robinhood (MUST), Google Photos (LIKE), Stocks (LIKE), News (LIKE) ...

I had never spent a single dollar on an Apple product till January 9th 2015, when I paid for a gold 16GB, iPhone 6.

I've only used a Windows Smartphone thus far. That was not too irrational given that I work for Microsoft. So what caused the change?

Financial

• I was due for an upgrade and each month that I did not upgrade with my plan with ATT, I was effectively losing money.
• So why didn't I upgrade to another Windows Phone (I currently have a Nokia Lumia 920)? I just don't see a next gen Windows Phone option to upgrade to. Maybe these devices will be timed to be released with Windows Phone OS 10 but they are just not there now. I don't see any indication of them or an upgrade timeline.
• An iPhone is just worth more on eBay if I were to sell it. If I didn't like it I could just get rid of it.

Technology

• It will be kind of fun to learn how a different Smartphone works even if it is from a competitor.
• Apple owners love their products. It would be good to understand why. Maybe once I did I might be able to credibly talk about the good aspects of the Windows ecosystem.
• The Microsoft mandate has been redefined as a platform and productivity company. It will be interesting to see how our products work on the iOS platform. 
• Apps. I don't use many but just for once if there's an app for something I don't want to hear that there isn't a version for my smartphone.

It will be an interesting experiment. My Lumia 920 will be carefully stowed away in case it needs to be called into service again!