Overpriced food in an amazing atmosphere (if you're imaginatively-inclined). Yes, the animatronic animals are outdated but they're still fun, as is the thunderstorm. I really enjoyed the fountain & statue of Atlas, though I'm not sure what he has to do with the rainforest or its animals.
The food is nothing special and costs 50% more than anywhere else. Except for their Volcano desert, which is AMAZING. For $16 you get a giant mountain of brownies and ice cream.
My suggestion is to have dinner in the Yorkdale food court, and go to Rainforest for their Volcano desert.