Hate to debunk the theory above, but I live in a town with a population of 178 and my iPhone service is abysmal here too, until I get to the big city where I practice (pop. 768 ).
Otherwise, love my iPhone, too! There is a great colorblindness screen, way cheaper than ishihari (sp?) books, and a hearing screener which works well with noise cancelling headphones and literally saved me over a grand compared to the audiometer I used at the big practice I left before going out on my own.
