I was there only about 2 years ago. I was staying on the Argentina side and took a bus over to the Brazil side. The main difference the Argentine side (Iguazu National Park) has the best close-ups views, while the Brazilian side (Foz do Iguazu) has the most spectacular panoramic view.
I remember taking public transport over to the Brazil side which was easy enough to arrange on the day.
Check out http://sevennaturalwonders.org/south-america/iguazu-falls/
it has a lot of useful info on the sunrise, sunset. Opening times etc.
Hope you have a great trip