As part of my on-going departure from the Evernote ecosystem to OneNote one of the things I've been trying to identify is functionality in OneNote that corrects issues I've previously had with Evernote. One of the main problems I had for years is the fact Evernote keeps everything in one big file. No matter what the item is, no matter how old it is, it's right there with everything else. While this can be argued as a strength I've always found this an unnecessary amount of content to be immediately available. Now, keep in mind there's a difference between immediately available and easily accessible.
One of the strengths I've found in OneNote is the ability to have multiple notebooks. Now I know you're saying, "but Evernote does that!" The difference is that OneNote notebooks are separate files. They can be selectively opened and closed as needed. If you're building an informational archive you may not need access to the notes you took on a trip three years ago, but may still want to get to them at some point, the multiple notebook model makes it easy.
A practical example
One example of this is I have created notebooks for each of my previous jobs and moved to those notebooks all the emails, contacts, and other information for those companies. The benefit is that I don't need to open these notebooks nor do I need to have them synced all the time. They're accessible when I need them, but not tying up storage on my mobile devices.