I know I very rarely use my phone for phone calls. For me, it's all about apps and the capabilities those apps have.
My own phones have all been Nexuses. The reasons being that I consider Apple fascist[1], and Android is the only alternative with the combination of lots of apps and a way of replacing both launcher and default applications with third party apps.
As far as I know, Windows Phone's launcher can't be switched out, in fact I just did a quick search and it seems like not even the default browser can be replaced! It looks like Windows Phone is almost as restrictive as Apple, except with fewer apps. How would that make for a better phone, never mind "easily the best"?
Now, I'm no fan of Google, and I don't like the direction they're taking Android in, cutting down the functionality of AOSP, and dragging more into their proprietary apps and libraries. It's just that Android is the least worst choice right, now, as I see it.[2]
[1] Controlling, capricious, patronizing, "do it our way or get lost" mentality; and a brand that is a magnet for narcissists everywhere.
[2] MS primarily cares about money; it's copying Apple because it sees Apple making money. But Apple doesn't care about money; it thinks it's better than you, and it attracts people who like to think of themselves as better than other people, with more discerning taste in expensive status symbols. Making lots of money is a side-effect of Apple's strategy, because it's harnessing a narcissism latent in modern individualistic consumer society. MS's strategy won't work because it's not appealing to narcissists. Google, meanwhile, is following Microsoft's 1980s strategy to Apple's 1980s strategy.