I disagree completely. I wouldn't trust anything important to OneNote, and it's hard to get things out of it again, too. Your notes are basically locked in. You can sort of print to PDF, but it uses different pagination to the original PDFs you annotate! PDFs are inserted as bitmap images instead of vector format, and text is only sometimes searchable.
OneNote has a really scary number of obvious bugs, with pen input especially. Writing disappears immediately or jumps left and right, the document randomly stops updating the screen, the program gets stuck in a high-CPU loop making huge input lag and needs restarting, selecting writing doesn't select what you draw around but a smaller area inside that, etc. It's incredibly frustrating and difficult compared to the Android pen-based notes app I use, Squid (which has a much narrower focus, but is much better at it).
My biggest issue with onenote is that you can no longer use local notebooks with the new versions. I'm stuck on onenote 2016 or all my local notebooks become read only.
One drive is blocked at work so onenote is effectively useless to me now.
For now, I've started moving my notes to a static site using hugo. It's a bit less convenient, but until I settle on a better permanent solution at least I have text files I can move around and manipulated in bulk if needed.
Yes, lock-in is a big problem we have with Onenote in my company, since Microsoft decided not to offer offline notes anymore. Lots of people have their notes locked-in that format and we cannot store that data on a third party server.
Export is really the weakest area of OneNote. As far as I can tell, there is no way of batch exporting that also exports embedded attachments (for example, if you embed a PDF or Word document into a page rather than "printing" to the page).
OneNote has a really scary number of obvious bugs, with pen input especially. Writing disappears immediately or jumps left and right, the document randomly stops updating the screen, the program gets stuck in a high-CPU loop making huge input lag and needs restarting, selecting writing doesn't select what you draw around but a smaller area inside that, etc. It's incredibly frustrating and difficult compared to the Android pen-based notes app I use, Squid (which has a much narrower focus, but is much better at it).