ipp: writing for sure (a-pen has its benefits in the built-in tech), but not for other stuff. apple pencil dont compete with fiftythree pencil at all. the Pencil 53 (walnut) feels great, quite surprisingly ergonomic and works great with the Paper app. it hasnt been done for writing in the first place. when doing something else than writing, i would pick up the Pencil 53 before a-pen.
and btw, you are compairing 3rd party manufacturers bt stylus to the tech supported stylus made by apple itself. ps. try to use a-pen with any other ipad or iphone ;-D