I agree with Marko that your composition (cropping wise) is good, and with the people in the photo.

As for the waterfall itself, i feel that the exposure time should be EITHER very fast (to freeze all of the droplets; 1/320 second or faster), or slow (from 1/6 sec - 2 seconds, or even up to 30seconds depending on your tastes - I like long exposures myself). To me, anything in between begins to look distracting, or gives your photo the impression that it's not sharp, even though your focus was right on.

Background is spectacular, though. Great job with the shot!!!