I have switched to WP for over a year now. At first, it was annoying because I am familiar with Android only plus I have a very deep love with Google (student life haha, I love their search engine to dead

.) Another downside is most of your favorite apps are not there, no official app from Google anymore, no online money earning apps (they are all fake if there is any, except Bing Rewards, almost zero work for extra cash, if you're interested can I send you my referral link? I haven't make enough to have a signature yet) and there are many awesome apps that are not available on Windows store.
To sum up, people usually have two common difficulties with it. First is a unfamiliar interface. And last but not least It is the shortage of apps, or if there is any, the updates always come late comparing to iOS or Android. I feel like I live in a different isolated world lol.
But trust me, you'll
looove it soon! Because both two points above are actually not true!
The way it works actually extremely user-friendly once you get used to it. I couldn't figure it out at first because... ironically it was too simple! You can do everything in a very few steps. Everything is there, right in front of your eyes. If you are a smart user you can make it even more efficient by pinning the right thing and organizing your home screen.
About the second point, I have so many to say. First, as to this point Windows market already has most of the popular apps by its own creator or alternative apps by indie developers. This is the awesome part, indie developers are more responsive to users. They personally interact and response to their app users which make their updates really work and be able to provide what we need and what we ask for. Most of these alternative apps work better than the official apps on iOS or Android (Pin it for Pinterest, 6tag for Instagram, Tubecast for Youtube, etc.) Second, I have exclusive over the top awesome apps only for WP Store! I missed my Wallet app on Android the most but now after a year I found a finance managing app that I have never imagined such an amazing app could exist! And I love my note taking, alarm app so so much! I have never felt this way before with Android. You can't find the same experience with any other type of OS. And third, the tide has turned, some apps actually appear on WP store first! I don't remember the name but I used to play a music game. It gained huge success on this market before going to other platforms.
A little perk I found out of it is I get used to Win 10 from Win 7 pretty fast cos I have been using a Windows phone

. I love the idea of universal apps.
At the end of the day, WP boost my productivity. It is the best for students or office workers. Ah...the office apps... I shouldn't rant too much but you know.. it's Microsoft

. Just like Android and Nexus. The best office apps are here (they are actually built-in).
And what really really awesome about it is you don't need to change your phone after a year or two. My phone is new but it is an old model from 4-5 years ago (Lumia 925). It works smoothly with every apps. With every new OS update some apps maybe not compatible but be patient, the developers will update it soon. Kudos to indie developers! Apps from big corporation usually sucks there.
Microsoft did a good choice to encourage indie developers but I blame their Marketing team. Their phone is really good but they couldn't get people to know that. I feel frustrated to talk to my iPhone user friends about WP. Seriously, I don't know why people use that overpriced phone just to have bad experience with it after a year (hardware and software glitches and bugs).
Plus, Bing search is not bad at all. ^^
Ps: Skype still sucks which is very ironic cos it's Microsoft product.
TL;DR: Switched to WP, loooove it since then. I don't have any intention to go back to other OS again. Good or bad it depends on whether you can utilize its ability or not. WP has huge potentials but you need to explore a little bit first.
................Edited............
I didn't know that I rambled this much @@. Again, I blame Microsoft Marketing team to make me make such a speech about how good their products are (lol).