You absolutely must be kidding.
vs Gardens by the Bay:
Credits to the authors.
@ADRM is entirely accurate.
While Gardens by the Bay is indeed much larger in total area, much of what it is, is the antithesis of nature.
Plants were sourced from all over the world, including a variety of different climate and eco-zones.
It may be wonderous in its variety, but that is entirely unnatural.
There are some areas of the gardens which provide a more natural landscape, but once you remove the buildings, super trees, and non-native plants you get an area smaller than the Lower Don Lands devoted to nature.
Nature being what would ideally occur without human intervention, and can be self-sustaining in the largest measure.
The Gardens by the Bay is many wondrous things, but that, it is not.
Also keep in mind that the Toronto project is not only the newly created valley, but wetlands to the north of Lake Shore, and the Don Greenway to the south.
In respect of costs, these are projects of similar scale, both in excess of 1B CAD.