Recs.
Updated
SpecsUpdate
Pros
Pro Offers flexible encryption
Unlike most other apps, you can selectively password protect, and fully encrypt, individual documents or entire folders. This is especially important to many people with data stored in the cloud. As of early this year, even the free version supports encryption. Microsoft has also enhanced their internal security methods for storing data on OneDrive (where OneNote performs sync), which makes it more secure than most of their competitors (including Evernote).
Pro Strong search features let you quickly find what you're looking for
If you don't want to search through all of your notes, you can narrow it down by specifying the page, section, group, or notebook.
You're not limited to just searching through your text either. You can search for text in images, video recordings, and audio (this is off by default).
Pro Sharing and collaboration
You can share your notes by inviting people with an e-mail, or by giving them a direct URL. You have control over what kind of access the user has on your note (read only, edit) and can revoke it at any time.
OneNote will alert you when a chance in made on your shared note.
Pro Supports hierarchical organization of information / notes
OneNote is designed to allow hierarchical organization of information. This is achieved with grouping into the following categories and UI elements (Notebooks, Sections, and Pages). Both Sections and Pages allow additional groupings that can be expanded / collapsed in list view.
This can be incredibly helpful for quickly taking notes and organizing them for work or personal projects.
For example, you could have a Notebook for "Cooking Recipes", with sections for "breakfast, dinner, desserts", where individual recipes would be page entries (i.e. the "Desserts" section would have pages for brownies, chocolate cheesecake etc).
Cons
Con Uninspired, bland user interface
Many of OneNote's competitors use Material Design and bold colors to create a minimal, clean looking interface.
OneNote has a bit more of an outdated look and can feel over crowded at times.
Con The added flexibility means your notes may feel cluttered
Since you can place elements anywhere you'd like on your note, you have to pay attention to how you structure it. For some this added flexibility is a huge selling point, but for others it could become distracting and makes notes feel difficult to digest.