I have answered a question, and based on feedback from the OP, most of my answer needs to be replaced/updated with the revised answer. My question: Should I append the new answer to the existing post so as to make the currently proposed answer as clear as possible; or should I leave the current answer and add on to the post with a clearly marked UPDATE section, which would have the advantage of showing the evolution of the answer as the question itself was clarified? The thread in question is here, if that helps any.
My preference would be to replace the current answer completely with your updated version. I find it distracting to read previous versions in-line only to have my thought process derailed by a sudden UPDATE or EDIT marker followed by a completely new answer based on feedback from comments or further thought by the answerer.
All edits are tracked in a public edit history automatically. There is little point in duplicating this feature in most cases. Common sense is a good guide here.