I've used Evernote for years. The note-taking service does a lot of things really well on mobile devices, such as clipping web content without mucking up article layouts.
For example, OneNote's freeform canvas structure makes it easy and intuitive to use the Apple Pencil (or your finger, or any other stylus) to draw not only inside images within notes but around them, too. Check out the video above to see what I mean.
In comparison, Evernote's more rigid structure only lets you draw inside images. If you doodle or use a stylus in a note to make other annotations, your scribbles become graphic inserts that are placed inline with your images or notes. OneNote's approach feels more natural, and it's much more useful.
I asked an Evernote spokesperson if or when users will be able to annotate with styli more freely, but he wouldn’t say what new features might be added down the road. However, the Evernote rep said the company believes "multiple inputs are important," and added that "while many people use thumbs today on mobile devices, voice and other inputs are part of the future (and the present for some of course)."
Until Evernote becomes more stylus-friendly, OneNote is by far the better option for freehand annotation and illustration.