Smartphone manufacturers are going to have to fight hard to keep their customers; 75 percent of smartphone owners surveyed by German marketing company GfK say they may switch to another operating system when they buy their next phone. The survey was conducted in October and November among 2,653 mobile phone users in Brazil, Germany, Spain, Britain, the US, and China. GfK also found that 37 percent of feature phone owners plan to upgrade to a smartphone when they buy their next phone.

"Loyalty with a handset is a lot more complicated these days in that people buy into experiences at the high-end level," Ryan Garner, an analyst with GfK, told Reuters. "If a phone doesn't do what it says it will do or what the owner hopes it will do, the maker will lose loyalty."

The iPhone had the highest loyalty, with 59 percent of respondents saying they were sticking with Apple's iOS. Research in Motion's BlackBerry was second at 35 percent, Google's Android was third at 28 percent, and Nokia's Symbian was fourth at 24 percent. Owners of smartphones running Microsoft software were the least loyal in GfK's survey, with only 21 percent saying they would stick to the platform. This is not too surprising given that Microsoft has only just reset its mobile OS platform from Windows Mobile to Windows Phone.