The big problem with the two markers mentioned in the post is they are not part of the visible character set. Using a comma delimiter is good as it is visible,

The big problem with the two markers mentioned in the post is they are not part of the visible character set. Using a comma delimiter is good as it is visible, you can just use a basic text view to see it. A tab delimiter is not preferable as it is not visible, and can be problematic to parse via command line tools (ie what do I set as the delimiter character?). I think that is the whole point of having ASCII delimited text files is to have human readable data in it.