I haven't had a slip but I've stayed at each one as a transient. I like Burnham the best. Diversey is poorly maintained in my opinion. The cheapest is "on the wall" at Monroe which is close to everything but you need big fenders and good lines.
I have owned a 28' Nordic, you might want to take a look at a 28' Sunsation. Alot better rough water Lake Michigan boat, trust me. Shogren has one cheap.