We did the Rain Forest Ariel Tram in Costa Rica last October. It was very nice and the tourguides were very good. However, you don't see much(if any) wildlife from the tram. I'm not sure if that time of year is different, but we saw little more than many types of trees. I found the bus to the tram to be much more interesting. We saw a sloth and the driver pulled off the road and the tour guide told us a little about the banana plantation.
I am likely to return to Costa Rica with my teenagers and will choose the Torteguero Canal tour. They would be bored with the Ariel Tram.