Most everyone agrees that soil is the way to grow the best conniseur level bud. Cannabis cup winning bud is typically all soil grown.
And most people will agree that hydro (regardless of type) is best for commercial crops. Faster finishing and more productive.
But nothing is black and white in life. There are crappy soils with chemicals that grow crappy tasting weed and there are hydro systems both chemical and organic that can grow some kick ass tasting weed.
Boils down to personal preference... Medical or not has nothing to do with it. Potency is genetic and only a tiny bit environmental.