This would really depend on the demographic. Someone that is more technologically inclined would understand. However, appealing to the broad spectrum the general public would not. However, that example has to do more with the domain extension rather than www. Another example would be the .co domain extension example. In the western part of the country it could be easily recognize, but in the Midwest the demographic is much different and the general public may feel that a .co domain is merely a spelling error. It's all about your user demographic and their perception. Go with non www and then a redirect. Unless your demographic runs on 2G, either way isn't going to drastically affect your users. I would be more concerned about your file and images sizes than 100ms of a redirect.