I'm surprised no one has mentioned GoodNotes. It isn't as full featured as other apps, but it has a great UI for note taking, in my opinion. I still fall back to Notes Plus and its handwriting recognition when I know I'll need to clean up and reformat my notes for publishing afterwards, but for casual notetaking GoodNotes works really well.
Thanks for the recommendation of Writepad. That looks like it could be a great replacement for Note Plus. I like Notes Plus but tend to agree that the UI can complicate the HWR process. And I love the fact that Writepad converts on the fly. I'll definitely be checking it out.