I was deeply disappointed with this tour, which is partly my own fault for bringing unrealistic expectations to the tour. When I think of a rain forest I think of exotic wild life and plants. In fact Tijuca rain forest meets the technical definition of a rain forest, in terms of rain per year, but is actually a hand planted forest with plants from all over the world. It felt like walking through a forest in Ohio where I grew up. Nothing special.
Because this forest is planted over a substantial amount of space in a mountainous terrain, it's elevation allows for stunning views of the surrounding city. That said, if you went on an island tour, to sugar loaf mountain, or to see Christ the Redeemer, then you've already seen stunning views of the city.