The latest mobile phone user survey from market research firm ChangeWave reveals similar levels of overall satisfaction between iPhone 4 users on Verizon versus those on AT&T. However, Verizon iPhone 4 users seem to suffer from dropped calls far less often than their AT&T peers, supporting early anecdotal evidence from Verizon iPhone users.

"In terms of overall satisfaction the two iPhones are virtually indistinguishable," according to ChangeWave vice president of research Paul Carton. In March, 82 percent of Verizon iPhone 4 users reported being very satisfied with the device, while 80 percent of AT&T iPhone users reported the same. Only two percent reported any dissatisfaction with the device on either carrier.

That doesn't mean users on Verizon don't see at least one significant benefit: fewer dropped calls. Verizon iPhone 4 users reported a dropped call rate of 1.8 percent. AT&T iPhone 4 users, in contrast, had a dropped call rate of 4.8 percent—more than double that of Verizon iPhone 4 users.

That difference isn't limited to iPhones, though. Comparing dropped call rates for all mobile users on all four carriers, Verizon users reported just 1.4 percent of calls were dropped unexpectedly, while AT&T users reported a 4.6 percent rate. T-Mobile and Sprint users reported rates of 2.3 percent and 2.7 percent respectively.

A look at ChangeWave's historical data suggests that AT&T is actually improving. At the height of the iPhone 4 release, AT&T users were reporting dropped call rates as high as 6 percent—the highest rate recorded by ChangeWave's survey since tracking began in 2008. At the same time, however, Verizon has also been improving. The 1.4 percent rate is the lowest recorded since 2008.

While our own testing didn't reveal much of a difference in dropped calls, ChangeWave's survey results jibe with the accepted dogma about using an iPhone on Verizon versus AT&T—namely, that dropped calls were much less of a problem. If voice calls are a primary reason you use a smartphone, Verizon may be a better choice if you don't want your calls to unexpectedly cut themselves short.

UPDATE: An AT&T spokesperson told Ars that research using drives tests performed by Global Wireless Solutions suggested its dropped call rate is much lower than that reported by respondents to ChangeWave's survey. The company reported a 1.41 percent dropped call rate in November last year, and noted the figure was just a tenth of a percent higher than the lowest recorded rate among all carriers. (It's not noted, however, which other carrier had the lowest rate.) That's slightly better than the 1.44 percent dropped call rate the company reported this same time last year.