UW - Milwaukee focuses the majority of their decision off of your academic stats & GRE scores, whereas UW - La Crosse takes experience, recommendation letters & other factors more into account. UWM uses a statistical algorithm to calculate your likelihood of passing the boards (they're very focused on keeping their 100% pass rate) and they choose mostly based on that. UW-Milwaukee is also a newer program, so there are still some things they are working on, but their program is based off of UW - La Crosse's (they have a consortium). I know UW - La Crosse takes your overall experience more into account, but not to the extent that UW - Madison does. So if you're a very well rounded person & student I would recommend Madison. UWM would be a good option if you have great grades and GRE scores & La Crosse would be a blend of the two. It's hard to say which has an 'easier admission' since they are looking for different things in candidates.
I'm a 1st year at the University of Wisconsin (Madison). Our program is VERY diverse and we have an awesome group of people. I can't say enough good things about our program. Also, I was accepted into all 3 UW schools and I did my Master's at UW - Milwaukee. I chose Madison because of the great faculty, research opportunities, respect of the program & the Big 10 environment.
In the end, they're all great programs & will give you a great education. Any one would get you to where you want to be. Feel free to PM me if you have any more questions.