Nothing too tricky about this one. It does one thing, and does it well. While the other contentment-enhancing facilities either eliminate drones, enhance Psych or both, the Paradise Garden gives you a couple extra Talents, to offset whatever drones you may already have to deal with.
Comming rather late in the game, the price to build the Paradise Garden is quite reasonable, but that's offset by a substantial maintenance cost.
The Paradise Garden and the Punishment
Sphere are antithetical facilities. You can build one in any given base, but
you can never build both.