I have visited about four different Wisconsin State Parks over the past four years.  So far our camping experiences have been very good! The State Park System is very much like the Minnesota system.  The only difference I have seen is the way in which they charge for season passes.  Wisconsin charges from December to December so if you buy a pass mid-year, it will only be good for the rest of the year (or you can buy a daily pass for around $11.00).  In Minnesota, when you buy a yearly pass it is good for 12 months.