OneNote feels more like a piece of paper, where I can jot down exactly what I want where I want. To me, Evernote feels more like a collection of post-its.
And this may have changed, but at least taking notes for math etc. worked much better in OneNote.
Edit: Heh, the other commenter thought of Evernote as post-its as well. :p
Evernote appears to me as a thoughts organizer - its focus is heavy on managing notes, and its note editing features are pretty sparse. For my use case, Evernote seems horribly over engineered, as it is my note taking that is complex, but the management of my notes is rather simple. For simple notes and reminders, Google Keep has replaced it completely (and I was a Pro user for a while).
I've always envied OneNote on Windows (Phone), and will definitely try this. Its rich editing features appear to be much more suitable for better, you know, note taking.
Its pretty equal. There is more microsoft integration (obviously), and its setup more like a notebook rather than evernote which feels more like digital post-it notes. Not sure how sharing/colaboration compares.
I've never felt safe with my data with Evernote. They have been hacked quite a few times and sent me password change email requests as well numerous times.
Plus, I've lost post due to sync error on Evernote between devices often, mobile app is pretty poor - crashes often :(
