Better service = higher satisfaction. It's as simple as that, according to the latest ChangeWave cell phone survey. Verizon (VZ) - the perennial leader in customer satisfaction among cellular service providers - wins it again with a 42% Very Satisfied rating.

Tied for second, a distant 14-pts behind, are AT&T (T) and T-Mobile with 28% Very Satisfied ratings. That represents a 2-pt decline for AT&T in customer satisfaction since our January survey.

Customer Loyalty. Whether its sheer merit or sheer repetition of the annoying "We never stop working for you" jingle, Verizon customer loyalty is thriving. Only 10% of its current customers say they plan to switch to another cellular provider, an industry-wide low. Funny thing though, while AT&T customers say they're far less satisfied, AT&T's churn is just 11%.

So what gives? Why are their customers so loyal? And why are more people saying they'll switch to AT&T (28%) than Verizon (22%)?

The answer is the Apple (AAPL) iPhone, which looks set to capture more than a third of smart phone sales over the next 90 days, according to the ChangeWave survey.

AT&T's exclusive contract with Apple has clearly given it an advantage over Verizon - even if Verizon is by far the better service. So in hindsight, based on the numbers so far, AT&T's decision to hook-up with the iPhone looks like a marriage made in heaven.

Now if only their customers were happy and the EDGE network weren't so awfully slow...