I use a little Sunshine Advanced Mix #4, (basically Pro-Mix), mixed with Roots Organic 707, which is really good soil, and grow stones. I tend to go heavier with the 707 than the Sunshine. I used to amend my mix with different stuff but, I don't bother any more, now I give them all their feed from a bottle.
It seems like the amount of time my plants are in the pots isn't really long enough for things to break down enough to be useable, kinda started striking me as being a waste. I just go with the bottle and teas for them.
If I was growing outdoors or going for real long veg times I would do soil amendment.