The positive shifting view of legal marijuana is causing some states to have competing legalization initiatives. Arizona legalized medical marijuana in 2010 allowing the cultivation and sale of medicinal pot to patients, but some of the medical dispensaries are worried about legalizing recreational marijuana and stunting their own sales. The two groups currently campaining for legal marijuana have similar bill proposals, but both are great for consumers and a no brainer for voters.
There don't appear to be substantial differences between the MPP proposal and the dispensary proposal. Both give preferential treatment to existing dispensary operators. The MPP proposal allows for home growing of six plants while Medar's proposal allows for twelve plants. The two also differ slightly over penalties for possessing more than the personal amount allowed by law. In one written comparison, Medar's proposal appears to be looser than MPP's initiative.