If people don't look at the URL there's no usability issue either way, so you might as well use the www version for technical reasons. This (sub-)discussion pe

If people don't look at the URL there's no usability issue either way, so you might as well use the www version for technical reasons. This (sub-)discussion pertains to people who do look at the url. (And personally I agree that the www helps to denote a url, and so it's a net positive for users, or at least not a net negative.)