I don't use my stylus pen as it doesn't seem useful
Can any body tell me what application they use it for unless you want to draw otherwise if you have a keyboard i don't see the need for it.
Unless you know something i don't
DrawboardPDF for annotating PDF documents, OneNote for Note taking during meetings where typing is considered rude, PowerPoint to annotate slides while presenting or teaching. Reviewing Word Documents, Highlighting eBooks, use as a mouse when standing and cover isn't a viable solution...
OneNote for taking notes in class.
Best thing since slice bread. You can type as you normally do, and when comes special symbols, diagrams, charts, sketches, math, physics, chemistry drawings, you name it, you can in a sec, turn your SUrface Pro 2 into a tablet, and do what you need to do, and return back to keyboard typing.
OneNote is the ultimate note taking software, in my books. Nothing comes quite close to it.