To be honest, I stay away from anything that has Miracle-Gro in the title. I've heard that Foxfarm's Ocean and Forest is great for MJ, as it contains a high perlite ratio and other organic materials like woodchips, etc.
In my experience, I've always used Pro grade HP (high perlite ratio) soil, which can be found at any nursery if you just ask for a soil with a high perlite content. It might be cheaper than Foxfarm's but will definately be easier to find.