I preferred the Iowa State Fair to the Minnesota State Fair. I've been to both more than once and the Iowa fair just seemed less commercial to me. We all love our _____ on a stick but there was just too much of that at the Minnesota fair. Plus the Skyglider at the Iowa fair seemed better too.
Neither are in an even remotely rural setting, unless you count some of the people coming in from the corners of both states. Minnesota's seems easier to get to with busses coming in from anywhere in the city/suburbs. Iowa's you have to drive to a lot pretty close to the fair to get bussed over, but still not much trouble.
If you are travelling in from out of state keep in mind that Minneapolis is a more entertaining town to be in generally if you plan on spending several days. Des Moines is fine, but is just not a big city.
Born and raised in Iowa, Minneapolis resident for 3 years.