2008 -- In short, the 2008 laws provided a legal use of marihuana for medical purposes only by qualifying patients, and allowed caregivers to register and provide qualifying patients the marihuana. It also limited the amount of "usable" marihuana the patients could possess and the number of marihuana plants that could be grown. Marihuana dispensaries (selling) were not allowed.
2016 -- The 2008 laws are still in effect, but the 2016 laws allow for a series of commercial-like medical marihuana licenses: growing, processing, safety compliance (testing), transportation, and provisioning center (selling). Fewer restrictions apply, and the number of plants allowed to be grown may be well over 1,000 per license. A qualified patient or caregiver may purchase medical marihuana directly from a licensed provisioning center (dispensary).
Recreational marijuana is not legal in Michigan at this time.