How is this calligraphy written? How to appreciate the quality of writing?

The brushwork is very good, so is the layout of the work, the echo between words, the connection and inheritance. It's just that the shelf structure of words is debatable. Many words are written like pens, which do not meet the standard of brush writing. Probably I haven't been to a regular copybook, or there are not enough copybooks. Because some strokes belong to "wild pen". Such as Confucianism, boundary and tolerance.