- app organization. One swipe and I'm looking at an alphabetized list of apps I can jump to by letter. This is huge to me, so much easier to find and identify an app versus a 2d grid dominated by icons.
- live tiles. My email tile shows me unread emails, photo tile shows pictures, calendar shows appointments, etc. Small thing but makes life a little simpler and makes my home screen look nice.
- settings are organized and laid out in what seems to me to be a much cleaner and logical way. I think this may have regressed some in win 10.
- maps are offline by default. Saves on data and helps out a lot when going through poor signal areas, which I do a lot.
- Cortana is super awesome, ime works better than google now.
- I can deny apps individual permissions.
- OneDrive integration. I didn't use OneDrive prior to buying the phone but since it was auto installed on my win computers i started using it and its very convenient.
A lot of it just all the minor usability and ui struggles just aren't there. To me it's a lot more polished and easy to use. I may have bad taste. :)