Gary Kim does a great job explaining in an article that Customers will put up with a a lot of imperfection in service quality as evidenced by the 1% churn rate of AT&T versus the industry average of 3%. One wonders however if this staggering low rate isn't just consumers not wanting to give up their iPhones.
Kim also mentions Verizon in his post and I agree that the real test comes when the iPhone gets offered on this network - if ever. My experience has shown that around 50% of AT&T users would switch to Verizon based on casual conversations. The impact of so many millions of customers switching carriers would obviouslyu mean the burden of supporting all this wireless data will switch from one carrier to another quite quickly.
This brings us back to AT&T who has a limited amount of time to improve it's network before it has to deal with real competition from the Verizon iPhone, Droid X or new Blackberry device said to be yet another iPhone killer.