I went to UW's admitted students weekend, but was unable to go to UMN's. Honestly though, I'd still go with UMN. If you're a Wisconsin resident, you'll get reciprocity at UMN (~20k/year tuition) and the school really does seem to be better.
I love UW, and for many years it was my top choice for law school, but I think there are many other schools which will give you a great education and better opportunities. Given the choice between Madison and a school of similar rank, I'd pick UW in a heartbeat, but I don't think that UMN and Madison are really on par with each other.
All this can probably be discounted if you're planning to practice in WI, though, in which case you should take the lower tuition and enjoy yourself in Madison.