Not too expensive to visit (adults: $20.25, students: $14.75, child: 10.25) but overall pretty underwhelming. While I enjoyed the novelty of how the different environments were presented, I thought that the entire Biodome was too small and could've been organized more efficiently.
Pros:
Rainforest exhibit was quite true to life - it was super hot and humid in there, and we got a chance to see some parrots and other wildlife.
Penguins! It's not often that I get to see penguins (I don't believe the Toronto Zoo has them)
Underwater exhibit - I loved watching the schools of fish swim by, watching the occasional diving bird plunge into the water.
Cons:
Layout - the Biodome is laid out in a way that all guests will start at one point (the Rainforest) and will walk through the remaining exhibits in a sequential pattern, ending at the penguins. While this gives the guests walking through it a sense of following a narrative, certain areas get quite congested at times and it can be difficult to truly enjoy the exhibit. If the Biodome was laid out more like a zoo (as in, exhibits are separate of one another and you don't have to walk through an exhibit to get to another one) it can allow the patrons to re-visit a crowded exhibit at a later time.
Size - it's small. It took us maybe 1.5 hours to walk through it (going at a slow pace).
Poor signage - certain exhibits weren't labeled as to what animal we should be looking for in it. Made for a confusing time.