It was said that the Brazilian side was better, because they have the best panoramic view. That is right, but I didn't find the whole park better at all. I think most of the falls are too far, and some of the most impressive falls, are hidden by San Martín Island. And to visit the Brazilian side it took me a couple of hours, since for the Argentine it took me the whole day to enjoy de different circuits.
In Argentina you get wet with the falls and in Brazil you see them from far.
My advice is to visit both sides, because there are different views, and different ways to enjoy this wonderful place from one side and another. But if you don't have time, or want to have a view from only one of the sides, the Argentine is much better and varied than the Brazilian.
This review is the subjective opinion of a TravelPod member and not of TravelPod.com.