Ive had a galaxy tab for a bit over a year now and use Notewise.

Its not foss but fuck me its the most comprehensive note app ive found for use with pen.

I use it to mark up construction plans, edit PDFs, sign documents, design things with its protractors and rulers, take notes, read manuals, its really above the rest in every way.

I do use Joplin for general text note taking in a notebook style but Notewise for anything and everything else.

edit - it also saves documents in i believe vector format so you can fully zoom in to your writing / highlighting and its never blurry. I found that samsung notes was absolutely horrible after you exported anything to pdf or image.