It all depends on your needs. For me, Noteshelf is, by far, the most intuitive, most reliable and easy to use. Give to an 8-year old kid a tablet with Noteshelf installed and he’ll get familiar with the app within minutes (I have seen it!).
For fast notes (like quick reminders, or brainstorming ideas) I use Notability because I like the continuous vertical scrolling that does not disrupt my process.
So if I were to make a top 4 I would say:
- Goodnotes 4 (unfortunately this will be out of the market soon)
- Goodnotes 5