PoolManager, the original and best instance pooling solution for Unity, manages instances more efficiently to increase performance, organize the scene hierachy and is simple to implement. If you don't believe us, check-out the reviews here and on our website.
When an instance is needed over and over why destroy it? Re-use it! PoolManager has many additional features, such as preloading instances so they aren't instantiated during game play and shuriken auto-despawning, to help you develop and run your game faster. See the link below for details.