I'm ordering a Mini S from International as soon as I have an idea when my house will be finished (probably be ordering in the spring or summer--hopefully sooner, if I can decide on a friggin' color!). I spent a couple of hours there, asking questions and driving the Mini and Mini S this summer, and stopped in more recently (I'm an hour and a half away, but was passing through Milwaukee) to check out the new colors. I'd strongly recommend Anthony--he knows his stuff, and more importantly, he's honest--if he doesn't know the answer, he won't b.s. you; he'll look it up or do the best he can to find out--and if the answer isn't there yet, he'll tell you. He's about as low pressure of a salesman as you'd ever meet--helpful without being pushy.
A couple of other plusses for International is they don't mark over MSRP, and you can get some fairly nice customization done--like color coded wheel arches, etc.
Can't speak for the service department though (although I'm hoping it's as good as the sales department) as I don't have any experience with it.