I use my left over Fox Farm soil for tomatoes and when I run out I'll usually just go buy MG because it's cheap and you can get it every where. This season I actually compared and the MG tomato plants flowered and fruited quicker than the Fox Farm tomatoes. More often, too.. But, the FF plants grew larger fruit that was of higher quality. Fewer seeds and less membrane(that slimy stuff around the seeds), lots of sweet flavorful meat. The MG tomatoes had larger seed cavities and a bit more seeds, much less "meat" and much more pulpy membrane. They were very similar to the quality you would find at a grocery chain.. They didn't taste as robust and sweet either. This is my FF/MG comparison.