Nice for kids. The last time I went was when I was 16, and this was 2 years ago. My (at the time) 11 year old brother enjoyed, while I was absolutely bored out of my mind (until the waterpark). They have a drop tower which is about 30 ft high which again, great for kids. But there's really no rides here for teenagers or adults
The waterpark was amazing, though. Without the waterpark, this would be a 1-star review instead of a 3-star review. A decent number of large waterslides; what they lack in rides, they certainly make up for with the waterpark.
I don't remember much about Ontario Place other than that, but I do remember that the food is quite expensive. They could really improve by upgrading the place so that it appeals to more age groups.