It's well known that fans of Apple's iPhone tend to be loyal to Apple. There are even creative names for die hard iPhone users, like "Apple Fanbois" and "iSheep."

But a recent survey from Rebtel, a Voice over IP (VoIP) provider second only to Skype, reveals that iPhone users are more likely to be loyal to their cell service carriers as well as to Apple.

Of the 992 U.S. mobile phone users polled, 29 percent of iPhone users said even crappy service isn't likely to persuade them to switch mobile service providers.

In contrast, only 19 percent of Android owners said the same. It seems Google fans aren't as willing to put up with lousy service as Apple fans are.

As far as the importance of call quality, 89 percent of respondents said that it's important to them to have clear and consistent calls. Of those, 84 percent said they'd switch phones if the quality dropped too low.

And 78 percent said they might switch carriers if network performance or speeds dip.

Plenty of those surveyed experienced poor service lately, with almost 40 percent responding that they generally experience five or more dropped calls a month.

Locked into loyalty

A phone's manufacturer has little to do with call quality, so it's unclear exactly why Apple users might feel more loyalty to AT&T, Verizon or Sprint than Android users do.

One possible explanation is that some Android users aren't locked into contracts, making it much easier for them to switch carriers if the service disappoints them.

iPhone users, on the other hand, don't yet have the option of going prepaid.

However, the survey didn't make it clear whether this was a factor.

Via MSNBC