It would depend on how they left the comment. I have no problem with people disagreeing with my ideas/opinions, so long as the state it in an educated way. If people leave moody/derogatory comments, then I think that reflects greatly on their personality and I just ignore them. In fact, often I will leave their comments on a page, so that other hubbers will know what they are like too.
However, if I have made a mistake, then I prefer that someone mentions it to me. When I do this for other hubbers, I normally leave two comments. The 1st will be about the hub, and the second will be about the error and advising them that they are welcome to delete that 2nd advisory comment.