Hey stealth,
THe issue most growers have with MG other than the fact that it's chemical (not even organic-derived if I understand it right) is that those little pellets in the soil are time-release fertilizer, which make it very difficult to dose any nutrients you might want to add later. I've never used it myself but I would imagine this would also make flushing your soil pointless and give your bud a harsh taste. That said, if you don't ever add any nutrients, it might not be so bad...but you risk having problems with nutrient levels and have less control over what your plants are eating.
For the best/cheapest soil, you might consider making your own mix with peat moss, perlite, worm castings, vermiculite, coco, etc. If you look around the forums you'll be able to find a mix that works for you and whatever feeding schedule you decide on.
If you want something that you can use pretty much right out of the bag, there are lots of options. Your local gardening store/nursery will probably have some bagged organic soil (about 10$ a bag around here) or you can pick up one of the fox farm soils ocean forest, planting mix, happy frog (a lot of people, myself included like the ocean forest), but those will probably run you around 20 bucks a bag, although you should probably cut it down with some perlite for aeration and to dilute all that food...
I've only ever used the fox farm liquid ferts (which work great and I would definitely recommend) so I can't really help you much with picking nutrients.
Also, did you maybe grow bagseed last time around? Keep in mind that the quality and yield of your bud depends mostly on the genetics of your seeds and only marginally on your growing skills. You can always fuck up your harvest if you suck at growing, but you can't grow dank buds from shitty beans no matter how green your thumb is....