Notability hands down.
I have switched back and forth between it and OneNote, and I've tried GoodNotes. OneNote has a habit of jumping around when you try to write notes. It is aggravating and I've dumped it entirely after giving it several chances. GoodNotes never really did it for me. Notability does pretty much everything I want with one exception: I like a function in OneNote where you can draw a line within the notes and pull down the notes below to make space for new notes on the page. Notability doesn't do that, though many have requested that functionality. Everything else, though, is awesome.