We visited the Biodome today and my entire family - my parents, brother, husband and son loved it. The animal environments and the animals themselves were great. My son loved the penguins. The penguins were very playful, so they entertained my son for quite a while.
The sitting area with flowers and chairs was also great for resting and for taking turns using the restroom. The souvenir shop had a great variety of items and my son definitely loved several things in there.
My main complaint is the price is a bit steep for what it is. Entrance fees for five adults (my son was free), was about US $85. For that price I expected a bit more to do (we probably sent 1.5 hours here, and only because my son loved the penguins and stayed there for a while).
Overall it was a good visit and I'd recommend it to others visiting the Olympic Park.