The Argentina side gives you a different view and brings you closer to the waterfalls, mostly on top of them. There is a lot more walking involved on the Argentina so plan for a full day. The train will get you to the trails, however it comes every half an hour so it does take a while. You can take a 15 minute walk to the Salto Mbigua waterfall, it was one of the main points for a scenic lookout. Also, you cannot miss the Devil's Throat- a 279 foot high where the river flows over a cliff into a bottomless pit. The mist from this waterfall will be sure to get you wet!