There is currently 1000 characters limit on comment. However it seems to count on converted HTML message length instead of characters typed in, so if your comment includes code snippet, this limit will be hit easily.
Currently we will either be forced to create new Answer, or for we moderators we can create Answer than convert it to comment. Creating new answer seems sub-optimal to me because the "line of discussion" is broken.
I would be glad to see the character limit is relaxed at least for Comments on Answers.
