On the market for just over a month of the three months ending with October 2014, the iPhone 6 Plus captured 41% of "phablet" sales - sales of smartphones with a screen size of 5.5 inches and larger, according to Kantar data. Phablet sales represented 10% of overall smartphone sales, up from 2% for the same period in 2013, the market monitoring firm said.

At the point of sale, when asked what drove their choice of smartphones, 58% of those surveyed who bought an iPhone 6 Plus said screen size was the primary reason for choosing their device. Despite the more compact design of the iPhone 6, 60% of consumers who chose it also cited screen size as the primary purchase driver. The ability to connect to a 4G/LTE network was the second most important reason cited by both buyer groups.

Although selling for just over a month, the iPhone 6, with 33% market share, became the best-selling model among iOS devices for the three months ending in October 2014. The iPhone 5s was the second best-selling iPhone model with 26%, and the iPhone 5c was third with 18%. The iPhone 6 Plus captured 10% of iOS sales.

In the Android camp, the Galaxy S5 remained the best-selling model with 22% of sales while the Galaxy S4 continued to show its longevity, maintaining second place with a share of 12%.

Of the iPhone 6 and iPhone 6 Plus buyers, 85% were repeat iOS buyers and 9% churned from Android.