Am I the only person who habitually emphasises to all their students the importance of presentation? So often people seem to halfarsedly cobble together an argument, and hastily pretend to format, proof read and cite it. These things are important. They cannot, of course, make up for a lack of content or failures of argument, but they can mitigate them to some degree. Alternatively, when a well presented work is presented in conjunction with good content and arguments, the work as a whole is likely to be better received than will a shabbily presented one.
I also see a strong positive correlation between those who worry about their presentation and those who have otherwise done well in content and argument.