It was never really the actual products themselves why I dislike MG. It has always been the owners of the product, and their conduct.About 20 years ago, I seen a lot of people successfully use MG. As years went by it seemed like everyone switched to the organic soils. A lot of people did complain about the time released nutrients. A lot of those people were also the ones that were brainwashed by hydroshops to buy THEIR concentrated nutrients and line of snake oils. I admit, I was one of those people. I never used MG but IMO if you're growing a plant long enough, those time released nutrients in MG should get used up. If you have a strain that you think may be sensitive to the MG soil, you can always cut the MG with a promix. I also bet MG is cleaner of bugs than FFOF. When I used FFOF I would get fungus gnats and those damn bloody root aphids. I prefer making my own organic soils myself but I'm also all for MG since I have seen it work.
It was also part of the reason (although not a driving one) why I switched away from GH products.