The hike to the falls was beautiful- along the river and surrounded by jungle. It was an intermediate hike, some steeper climbs and uneven terrain. The hike to the upper falls was definately an advanced hike. Luckily others had tied ropes in the steepest parts to make it easier to get there. We wore tennis shoes and were VERY grateful we did, however, bringing a pair of sandals with you once you get to the falls isn't a bad idea.
We were here in the dry season, so I imagine the waterfalls weren't as magnificent as when there is more rainfall, but they were still amazing and made for excellent pictures. There were arrows and lines painted on the rocks that made you more confident when jumping. We got to see a porcupine as we went early in the morning to avoid crowds (which we accomplished and didn't see a soul until we started back towards town.) We saw a Jesus Christ lizard, howler monkeys, iguanas (of course) and different species of birds.
Going early in the morning is definately the way to go so you can have a private fresh water swimming pool. We got to the upper falls about 7:30 and left about 8:30 and passed four or five large families on our way out. It took us about 15 minutes to get to the falls and about 25 minutes to get to the upper falls. Even if you aren't interested in jumping (which was totally safe if youre smart about where to jump or just follow the arrows) it is worth the hike up just to see the beauty!