I use miracle grow or black gold soils because they're all that's available up here. I lean toward the miracle grow, but only because it's less expensive. I've been pleased with the consistent performance of the soils. I've burned roots for sure, but I've been able to trace the damage back to my errors, generally in overfertilizing. I've not lost clones to miracle gro, and I've not noticed any wierd nutrient-uptake issues with my plants.

I fert with miracid at 1/2 strength every other feeding. It keeps the ph right where I want it and the plants seem to like it fine. I'm still working on finding the best bloom-period fert, but rapidbloom doesn't seem to hurt the plants any. Personally, I look at the big 3 numbers and the trace elements when I buy a fertilizer. I don't want anything too "hot", and I don't care for a lot of organic nutrients in my indoor garden. I think it promotes mould and critters. I don't think the plants know or care where their N, K, and P come from, as long as it's there.