Is Operating While Intoxicated (OWI) worse than Operating While Impaired (OWI)?

Yes, Operating While Intoxicated (OWI) is worse than Operating While Impaired (OWI)?  Operating while intoxicated is a 6 point ticket.  Operating while viably impaired is a 4 point ticket.

How many points is a DUI in Michigan?

Michigan has a 12 point system.  At 12 points you lose your license for having to many points.  A conviction for an Operating while Intoxicated is 6 points. A conviction for an Operating while visibly impaired (Impaired driving is a lesser offense) is 4 points.

How long does a DUI stay on your record in the state of Michigan?

A DUI conviction stays on your record for life.

Is a DUI a felony or misdemeanor in Michigan?

Both.  DUI first offense and second offense are misdemeanors in Michigan.  DUI third offense, DUI causing serious impairment, and DUI causing death are all felonies in Michigan.  Misdemeanors are punishable by less than a year in jail.  Felonies are punishable by more than a year in jail.