I think the arguments in favour of tabs are pretty strong. But there are a couple of small issue: - You can't have aligned tables of data / blocks of comments

I think the arguments in favour of tabs are pretty strong. But there are a couple of small issue: - You can't have aligned tables of data / blocks of comments / etc. if group of lines containing the aligned text have different amounts of indentation. - You can't place a fixed limit on line width (which many code formatting standards do, presumably to reduce horizontal scrolling and facilitate side-by-side diffs).