If you have plan to watch AVATAR by Cameron on cinema, skip reading the plot on wiki: http://en.wikipedia.org/wiki/Avatar_%282009_film%29
While watching on 3D in IMAX theater, I felt being dizzy at times.
Although the viewers are (sort of) trained in the beginning to focus on clean-focused drops to follow the camera focus, many will find their view dimmed due to instant change in focus depth on the screen.
From my experience, I would suggest closing eyes for a sec(or half). This makes one to be disconnected from the focus chase thereby allowing to see the picture.
Movie has been getting nice comments worldwide.
However, our big brother India has some nice dubbing capabilities for such movie.
I like (behind the scene) little technical details being presented here...