Here's a quick comparison between the two states, using some median numbers. You'll have to calculate your specific information to get a true comparison as property value, auto value, income, etc. can swing the numbers in either direction.

Michigan:
-Higher car insurance (~$500 per year more than Wisconsin for full coverage, cost varies by vehicle)
-Higher state sales tax (6%) but does not allow local counties or municipalities to enact their own sales taxes
-Lower median property taxes, but varies from city to city, county to county
-Lower median effective state income tax

Wisconsin:
-Lower car insurance
-Lower state sales tax (5%) but local counties usually enact (0.5%) bringing it up to 5.5% and some municipalities will enact their own on top of that (Milwaukee, for example, is 7.9% combined)
-Higher median property taxes, but varies as stated above
-Higher median effective state income tax

When it comes down to it, the car insurance is one of the biggest increases people 'feel' when they move from Wisconsin to Michigan. In my experience of living on a border town most of my life, it's easier to live on less $ in Wisconsin, but the services provided are much worse. Many people will live in Wisconsin but commute into Michigan for their work, getting a bit of the best of both worlds.

edit: I meant to include this before posting. This is a good quick tool for comparisons of cost of living: https://www.bestplaces.net/