We all know that Apple customers are a very devout bunch and, fittingly, a new survey found out that iPhone 4S owners are happier with their purchase than iPhone 4 owners.

The ChangeWave Research survey released Thursday compared the satisfaction levels of iPhone owners on key issues such as battery life, dropped calls, and overall likes and gripes - and the iPhone 4S showed marked improvement over the survey conducted last year on iPhone 4 owners.

Seventy-seven percent of iPhone 4S owners labeled themselves as 'very satisfied' with their iPhone purchase compared to the 72% that identified themselves as 'very satisfied' with their iPhone 4  purchase last year.

When it came to specific features that they best liked about the iPhone 4S, 49% marked the digital assistant Siri as the number one perk, 39% marked the general ease of use as the best feature and the 8 megapixel camera with LED flash came in third.

When the iPhone 4 was released, one of the biggest (and buzziest) complaints was the death-grip call dropping feature. With many users adding bumpers and covers, this problem became less of a concern.

The iPhone 4S users were asked about dropped call rates and the number of people experiencing dropped calls has, in fact, cut in half from last year's 5.2% to 2.5% -- but sadly, for AT&T and Apple, the researchers are basing this difference on the coverage quality of Verizon bringing up the curve.

Based on the survey, nearly two-in-five iPhone 4S owners are using other wireless service providers (i.e., Verizon, Sprint) than the, originally-exclusively offered, AT&T.

Verizon iPhone 4S owners reported only a 1.3% dropped call rate while AT&T iPhone 4S owners reported a 4.1% dropped call rate.

The biggest complaints seen by iPhone 4S owners continues to be the battery life that has been criticized, especially with the 4S release since many more features suggest that geo-tracking services and notifications be set for optimal use, but those services are battery drainers.

When respondents were asked about more specifics about using their phone on a reduced battery, only 8% responded that using the phone with a reduced battery was a 'very big problem.'

Shortly after the survey was completed, a new iOS update came through that targets battery life as an updated focus but, as an iPhone owner, I have not seen any improvement in that field as I still have to charge my phone every 15-18 hours.

The second and third most registered complaint are definitely consumers comparing the iPhone to Android capabilities -- is the lack of 4G network capability and the size of the screen.