Rainforests are much better for biodiversity, the problem with that for us is that if the earth becomes more like that in the future, we're going to see a lot more microbial diseases and pandemics. Mosquitoes that carry malaria, dengue fever and other such infections are just an example. We'll also have a lot more worm infections, in nations that have tropical rain forests, the parasitic worm infection rate is as high as around 1 out of every 3 people (especially if they walk barefoot.)
I love tropical rain forests too-- but to visit only. I've noticed I get very sick if I'm there more than 2 weeks. The water isn't all that good either.