Apple's iPhone 6 is almost six times more popular than the larger iPhone 6 Plus model among enterprise smartphone users, according to data from enterprise mobility vendor Good Technology.

September saw the introduction of many new smartphones, but the launch of Apple's iPhone 6 with its 4.7-inch screen and the iPhone 6 Plus with a 5.5in screen was arguably the biggest of them all.

Despite not being available for the entire month, the iPhone 6 models made up 17% of all of Good's September activations, according to the company's Mobility Index report for the third quarter. Some 85% of those were activations of an iPhone 6, whereas only 15% were of an iPhone 6 Plus, Good said.

"You have to think that the leap from 4 inches to 5.5 inches was a bit too much for some of the iPhone faithful. It's a big step up," said Nick Spencer, senior practice director at ABI Research.

Other potentials reasons for the smaller model dominating sales include lower cost and an unwillingness to develop in-house iOS apps for too many screen sizes, according to Spencer. Apple's share of all activations was 69% compared to 29% for Android and 1% for Windows Phone.

The split between the iPhone 6 and iPhone 6 Plus isn't too far off where the total market for 2014 will end up. Devices with a 5.5-inch screen size or larger are expected to have a 14% share of total smartphone shipments during 2014, according to IDC.

The report also shows how mobility is becoming important to enterprises, which are building more of their own customised apps. Custom app activations more than doubled quarter over quarter and grew by over 700% year over year, becoming the most widely activated app category, according to Good.

The report highlights how smartphones and tablets are used differently among Good's enterprise users, as well. Smartphones are primarily used for communication and to get quick access to information, while tablet users are using their devices for more involved document access and editing.

Good's Mobility Index report for the third quarter was based on data from about 6,000 companies around the world, the company said.