OneNote

It is very usable, but there are other products out there who offer more.
Things that could be better is folders, or organisation of notes.
Or better templates for when being used with a touch screen and a stylus such as on an iPad.
However, it is quite, it stays in sync, and is able to store stuff offline if you don't have internet.

OneNote’s notebook and section hierarchy makes it easy to organize and categorize information so you can find and access what you need. However, the search function, while powerful, can be tricky to use when searching for specific info in a large amount of notes.

I find OneNote incredibly usable. I'm fairly middle of the road when it comes to tech savvy-ness. The platform was very easy to learn and explore. I like that OneNote is no clunky and offers a clean interface. This is important when it comes to deciding if a tool is usable for multiple people.

Overall, OneNote is easy to use. Everything is intuitive and has a very familiar layout especially if you use Microsoft Word and Microsoft Excel. It has shortcuts that are simple to get used to and tabs work as you would expect them to. One can also utilize built-in layouts to achieve a very high-quality notebook without much effort. There are some more advanced functionalities that can be achieved with OneNote, but only when you have mastered all of the tools.

Even if it's not intuitive, you can easily save your work until you can figure out how to do something.