I had not heard of Julia before but found some saying it will not / will replace R / Matlab at http://stats.stackexchange.com/ques...hope-of-sticking-in-the-statistical-community
Hard to say, it would probably take a few years to properly take off. Also, the key reason to use R is not the language, is the user community. For all I know, by the time anything like that develops, I'll be retired and climbing full time in Thailand or Patagonia.