Saw it yesterday, and it's a great movie. Very convincing performances by all concerned. Cash is beautifully portrayed by Joaquin Phoenix, and June Carter is so well depicted by Reese Witherspoon that she ought to get an Academy Award for it.

There are also entertaining glimpses of the young Elvis, Jerry Lee Lewis, Roy Orbison, etc (by actors)....Cash was touring with a whole slew of famous musicians in the early days.

Phoenix plays and sings the Cash songs, and Witherspoon sings the June Carter songs too...very well in both cases.