i have grown a few times in the past with mg soil. and the only issue ive had with it is it burns smaller plants in the beggining.
i also used mg because it was what i had.
another problem with mg soil is it isnt clean. i mean it can come with spider mites and all sorts of shit in it. i have to say though i used it and had sucess with it. toward the end after youve watereed it a bunch of times the soil gets weaker and weaker, so about 5 or 6 weeks from start i had to hit it with grow big by fox farm and tigerbloom. right before flowering. once the nutes washed out it was like working with any other soil. one good thing is, if you add perlite and vermaculite for drainage, then toss in some blood meal, bone meal, and wormcastings, the only thing for over a month you have to do is water it. toss some guano in also. those nutes will hold it for a long time and i guarantee youll be happy with the results. good luck bro