@skicoak
I honestly love it. I'm sure there are better programs, but I don't have any interest in switching to something else, personally. I own articy:draft too, which is comparable, but lacks ease of use.
Here's an example of what one of my notebooks looks like:
You can create several layers of nested pages, and collapse sections to reduce clutter.
You can include images, graphs, tables, to-do lists, doodles and handwritten notes. It's pretty convenient! Also syncs online, which has been occasionally useful to me.
It's not specialized like Notebook.ai though, so you'd have to do more legwork to get it set up the way you want it.