Do you have an Amish community near you? There's a sizeable Amish presence in northern Indiana (think Shipshewana area) and consequently, we see Amish folks in the area all the time. Usually, they're out garage sale shopping, but occasionally you run into them at hardware stores or other venues.
I'm kind of conflicted where the Amish are concerned. The liberal-minded anthropologist is prone to the "we have much to learn from them" type of thinking, but at the same time one has to recognize they treat women more or less as chattels and are beyond reactionary on the religious scale. They don't, however, get in your face with any evangelical action, and one is either born Amish or they aren't.
I don't have any statistics available, but I believe a large portion (like around a third or more) of their young choose to leave the faith after rumspringa. I also understand that the lack of affordable farm land is another large challenge they face, as fewer are able to pursue farming and have to look to other (as in sinful worldy) trades and occupations for subsistance (you can see them working in factories occasionally).
What's your take on the Amish?