You can grow outstanding bud with just MG and water (and proper lighting). I guess the difference between outstanding and perfect is enough to make some of these guys want to spend every waking moment tending to their plants?
Some flowers I picked on Valentines Day. Grown entirely in Miracle Grow Potting soil, no additives. I used extremely low wattage lighting. 6 - 26 watt CFL's, 8 - LED bulbs, and 1- 100 w sodium. I grew 11 plants in less than 4 months.