As for me, I came to Windows Phones "by chance". It all started around eight years ago, my grandfather gave me his O2 XDA II because it was bulky - naturally it was a Microsoft Pocket PC. After liking the computer-like interface (and how it was so different from those around me :wink

, my next major phones all ran Windows Mobile: Windows Mobile 5, 6, 6.5.3...and then came Windows Phone 7, 7.8, 8, 8.1... and finally now Windows 10 Mobile (build 10581). So technically, I didn't begin by "choosing" Windows Phone, but rather I remained with Windows Phones by choosing to, and here's why:
1. At first, I liked the interface - back in O2 XDAII, the interface was more professional than the its contemporaries. I could also watch .mp4 videos/movies, while my "peers" wondered how;
2. I liked to be "different" (stemming from #1) - of course this meant that I can't use my phone while in open public transportation, but that also meant I could focus more on "watching" and observing people around me :wink:;
3. I was never interested in moving over to a different platform - something which I reflected on, and was later justified given the level of security implemented in Windows Phone 8;
4. The photos my Windows Pocket PC took before were better than those taken by most of its contemporaries (except Nokia smart phones which had Zeiss optics);
5. Luckily, when Nokia started making Windows Phones, almost all Windows Phones I later owned were all "Nokia", which naturally had Zeiss optics - something I look for in a camera (even in DSLRs).
6. I prefer the sleek design of the Windows Phones I owned. Of course, not all were as sleek, but in general the design has been consistent, at least for the higher-end phones.