I lived through that awful period of syncing issues with GoodNotes. My primary use is the iPad, so syncing wasn’t a deal-breaker, but when I wanted to pull up my notes on the Mac, it was frustrating. In my experience this has been completely resolved now and it seems bullet-proof.
I can understand the appeal of an ever-expanding canvas in Notability, but this was something I could never get used to. I like the confines of a single page to help frame my thoughts. I do agree with the problems of trying to write in the upper reaches of the page. My solution for this in GoodNotes is to start every page by writing in the center. After I’ve written a section, I’ll circle it with the lasso tool and move it higher in the page. In brainstorming an idea, I’ll find myself re-arranging things a lot in the app; this is super easy in the app and so much better than real paper and pen…
Also, really enjoying the new Apple Pencil and the tap to switch to eraser which I’m sure works in both GoodNotes and Notability… Very intuitive and I don’t lose my concentration as much now when writing or drawing.
Honestly, I don’t think you can go wrong with either GoodNotes or Notability. Comes down to personal preferences…