While in Foz do Iguacu it was nice to visit a man made structure to contrast with the natural beauty of the waterfall.
I did the 1 hour panoramic tour and 1 hour biological reserve tour. If I went again I would just do the 2 hour specialty tour which takes you inside the dam (wear long trousers and closed toe shoes if you plan on doing this).
The dam is huge and the guides give you lots of fun facts. I enjoyed this part of the tour. They have put a lot of work into conserving the forest and wildlife which was good to see.
I would give the biological reserve a miss. I expected to see some free roaming wildlife, but this was just a zoo in the middle of the forest. The guide was very knowledgeable, enclosures were decent, but overall it was not what I expected.