Sorry, i really think that good notes was the best app overall to writing and using as notebook, but there's so much more user friendly features in notability that i cant live without.. and i used both apps arround the same time. Ill say the features you could had to make this app simply perfect:
— the lack of a dark theme unless we get system wide dark mode is a bummer as i find your dark theme pretty good but i hate to use ios in dark mode
— the tool bar has too many items and takes valuable space from the screen, mainly if we are landscape. Could use the top bar wheres the document title to integrate the toolbar there and the title of the document would be somewhere else, again, notability does this perfectly
— the lack of auto straight lines and geometric figures after a long press is really one of those dealbreakers.. i know you have the tool for that, but that tool is simply too simple, you cant edit the figures properly and you cant interact 2 circles and make them have the same center and change the radius of each one, or move just one corner of a triangle , etc.. this is THE FEATURE you should really really copy from notability, and its the real dealbreaker for me
— The design of the folders is pretty boring and i know you could make something way more modern and less techie.. those blue archivers are clearly not the best looking folder icons you can use, and while at it, plz let us change its colours so we can set different colours to different content of the folder.. would be easier to use, like university folders at green, stuff at blue, job at orange, etc...

And than off course there are something youre just doing brilliantly and making me want to come back to this
— first is the templates implementations. I simply love the cheer quantity of templates you give but better yet, the best of all is the ability to creat our owns and use them! I made some with my sweet spot of number of line per sheet and different colours, i love this
— 2nd the file system you use is soo great. Folders and files are still the best way to organize everysingle thing, so nice job.
— 3rd, your palm rejection is soo much better than the one notability has... every time i rest my hand on the screen, in notability it jumps, changes the zoom, etc, but in GoodNotes, it never happens!! I set it to my most used hand position and sensitivity to medium and it works flawlessly!
— One of the coolest things you have is the auto-deselect the eraser as soon as you lift the pencil. It simply makes all sense when paired with pencil2 double tap to eraser