The most popular operating system in the world today, is Android. There were at last count over 2 billion Android devices running loose across the face of the planet. That beats out Microsoft and Apple, combined. The reason for this is that Android ships on really cheap devices into the developing world, where Apple and Microsoft focus on keeping some market advantage in the developed world. Apple iOS is still the most popular mobile device OS in the US and Canada, and Microsoft the most popular OS in many parts of Europe, and Russia.
But…Microsoft got squeezed out of the smartphone market. If you bought a Windows phone, and like the windows phone, what are you going to do to replace your Windows phone when the one you have dies? Especially if you aren’t a fan of Android or Apple? Not much, there aren’t a lot of alternatives to Android or Apple.
Blackberry is done.
Nokia threw in the towel on Symbian OS.
There is nothing else on the market with enough share to matter.
What I recommend…is buy a Microsoft Lumia now while they are still on the market to kick the can down the road for another few years, maybe hope that Microsoft will release the “Surface Phone” in 2019 http://www.windowslatest.com/2017/08/13/surface-phone-release-date-postponed/ . But if Microsoft leaves the smartphone market entirely, your choices are going to be some flavor of Android..or Apple.
If you are ok with a little tech work I recommend you buy a used smartphone that can install a custom Android ROM. There are a lot of forks off of the old Cyanogenmod OS, such as Lineage OS which is pretty nice. Shop around for a used device on the supported device list and follow the directions, boom, now you have a smartphone with all the benefits of Android, but not a whole lot of the corporate branding from the likes of LG or Samsung.
If you buy into the whole corporate culture that is Apple, well, you’ll spend a lot of money to do so but you also get the best customer service and support in the industry. Seriously, the Apple care plan is a pretty sweet deal if you have the disposable income to purchase it.
But still, I’m a cheap guy who buys refurbished laptops and surplus server parts to build workstations, so obviously I’m not rocking an iPhone. Even though it seems like Google is more “Gulag” than “don’t be evil” it’s the world we live in, and Lineage OS is pretty sweet.