I've always heard one is better for this or that, never anything consistent. The only thing that I've seen consistently is harvest time effecting finished product.

When almost all of the trichs are cloudy, your harvest window has begun. Harvesting early will maximize the cerebral effects of the strain you are working with, while a later harvest, when the trichs are starting to turn amber and the THC is degrading, will give you a more body-oriented stone. This is nice for painkilling (muscle pain in particular), anti-anxiety, and anti-insomnia purposes.