On what basis do you personally judge whether a piece of writing is good or not?

I read a lot of history and analytic books, documents and articles. In this genre of writing, the quality of research and references, the ability to substantiate an argument with facts, an open mind and the ability to make complex information understandable to a wide range of age and education levels are the hallmarks of good writing in my mind. As for fiction, what makes good writing is more subjective. I enjoy fiction that holds my attention and makes me want to turn the page to read more.  The writing should flow easily and the story not difficult to follow. If it does these two things and removes my mind from reality into the story then I know I am reading a good piece of fiction.

Despite being a subjective task, choosing what is good and what is "bad" mostly relies on comparison between various works of art of the same genre. However, I must point out that a good writer (or amateur writer), is supposed to read both good and bad so as to know what to adopt and what to avoid.

Writing goes through three stages, which are: adopt, adapt and adept. Therefore, knowing that to assimilate and what to shun through comparison and expert opinion is crucial to every writer.

Personally I do not judge writing to be good or bad.

A piece of writing sometimes may not affect me as maybe the writer intended, but that is not to say that the writing is not good.  Simply it could just be that moment, looking at the writing at a different time could bring a different reaction.

Anyone who has taken the time to sit down, write something and put it out there to be seen by others, has taken a step many, many people are afraid or think their too good to do.  Writing is not as easy as it can look.

A good choice of words will get my attention, with a flair from individualism from their work.  I like to read authors who are not afraid to step out of their comfort zone, use 'new' words, descriptive words which draw you into their world or which you can really imagine what is going on.  

I engage with writers who can take you on a journey, emotionally, mentally and physically.  Many a great film has come from a writer who has created a world or emotions which just had to be translated onto film and shared with world.

I should be able to put a book down, come back to it later without having to remember where I left off in the book - a writer who has that skill has gained a loyal reader in me.

Criticism is a completely different and independent discipline in literature. We are not talking about that because that is a vast field and is certainly not the domain for this forum. A written piece is good id you like it. It is certainly good if it synchronises with your thinking or adds to your knowledge. It is good if it makes you laugh or cry. Writing that reflects a part of your life is good and carries the ability to associate with your life, ideas, environs, philosophy, among others.  

Content, story, plot, and on how the write weaves his/her work.