i had some issue on my current grow with MG soil/perilite and sfghum. not arguing that its shit soil just saying it can be difficult on a first time growe like myself.
my next grow i will be using pro mix, homeade worm castings, happy frog nutrients and organic perilite. In my personal opinion, organics seem to be the easiest way but i dont really have any evidence to back that up. from what i have read it seems pretty good for first time growers as its almost impossible to burn plants.
i will add 1 more thing, if you go with the miracle grow, do yourself a favor and have the H tested, it may be fine and if it is then you dont have to concern yourself with the PH for the rest of the grow. if there is a PH issue its better to get it taken care of before you start growing then have to deal with it while your plants have developed a root system in the soil. you want a PH of 6.8 for soil if im not mistaken but 6.6-7.0 is alright. a perfect ph (6.8 will ensure you plants are able to uptake all nutrients that are made available in the soil, with a PH that is off you will get lock outs.
also read up on how to water using MG soils and products as they can release alot of nutrients when you water and potentially burn smaller plants especially seedling.
good luck on your first grow man, hope all works out well for you. if you wantt to check out my journal i used MG products and i dont want you to check it out to scare you away from them but to help you understand thier potential to harm your plants, when used properly they are great products so maybe you can learn from my mistakes.
Matt