I had an early Windows phone and loved it. It had crazy good battery life. It made common action super efficient. It got out of my way. It organized all my social media so, so well. Its autocomplete when typing was better than anything I've used to date (though, I hear it actually worsened over time). I miss that phone.
Seconding the keyboard: perfect spacing, pleasing fonts, fast animations and responsive feeling and hands down the best text prediction I’ve ever used: best suggestions, best balance between aggression and accuracy. You could write a word and have it return any matching emoji’s literally years before Android or iOS.