Following last November’s election, 28 states have legalized medical marijuana, and according to Gallup, Americans’ attitude toward medical marijuana use has never been better. As a result, the use of medical marijuana is soaring. Tapping into that growth could be a big opportunity for drugmakers GW Pharmaceuticals (NASDAQ: GWPH) and Insys Therapeutics (NASDAQ: INSY), two publicly traded companies with marijuana drugs close to commercialization. Is one of these stocks a better buy than the other?