agree with roblack
its very dependant on the type of plant.
how much water you want ti to hold
how good you want the drainage.
a growing medium is to anchor the plant
and provide the roots environment to get nutrients.
Personally, i like having several size particles. it provides places for water and air to get trapped.
so i use a fine sand (from my yard) a heavy sand, perlite, and compost.
(i like a fine, sifted, well broken down compost)
something like forest farms is very heavy in organic matter, but not much sand or minerals.
it would be good for forest type trees. Probably not so good for things like Jujube or baobob.
i like to lookup the geography, soil, climate... original habitat...
of the plant i am growing, to get a sense of what it wants.
PH is another thing to watch.