Most growers will tell you to stay away from MG when growing weed but its only because its the marlboro of fertilizers aka the big guys and they do not want Miracle grow getting there foot in the door.

As long as you know your nutrients or NPK & you don't over feed you should be fine

That’s up to you, of course, but I’ll keep doing what works for me.  I know it’s cheaper to use, maybe that’s why some people use it.  Growing organic isn’t cheap!