Corporate users are still buying Research In Motion's Blackberry service in massive numbers, despite widespread prior awareness of Microsoft and Vodafone's plans to launch a rival push e-mail service early this year.
Latest figures from analyst Gartner show RIM shipped 3.2 million Blackberry devices in 2005 - up from 2.2 million in 2004.
Forrester analyst Ellen Daley said Blackberry was still the most complete service at the moment, despite the doubts raised by RIM's patent dispute in the US.
"All the uncertainty surrounding the NTP/RIM court battles does not diminish the fact that RIM's Blackberry device and service is the optimal user experience for wireless e-mail on the market today," she said.
The downside of the Microsoft service, said Daley, was the fact that only limited carrier-certified devices were currently available, with only the Vodafone service confirmed as becoming available in March.
"Expect more in the first half of 2006," she added. But in the longer term, Daley said the integration potential of Microsoft's service made it a major threat to Blackberry.
"RIM has had some limited success in making the Blackberry a mobile application platform, particularly for small and medium-sized businesses." She said Forrester thought Microsoft would prove more viable in the long run because it offers an operating system that is familiar to business users, and the .net development environment is relatively easy to use compared with RIM's non-standard Java system.
Daley said she expected users to be prepared to support both Blackberry and Microsoft simultaneously, despite the expense. "RIM/Blackberry will still offer the best wireless e-mail experience available in terms of usability." But she predicted that users would, over time, migrate to Windows Mobile as mobile business applications start to appear.
Todd Kort, principal analyst in Gartner's Computing Platforms Worldwide group, said the signs were that Blackberry users were generally "staying put" for the moment because of the high costs of switching, the lack of suitable alternative devices, and the low probability of Blackberry's service being shut down.
Business users so far appear cautious about the new entrant into mobile e-mail. Alan Powell, IS director of Hanover Housing Association, said his was a "keep it simple" organisation that would not want to adopt the two services in parallel. "In our case, the fewer the suppliers, the better."
But with the US legal dispute still hanging over RIM, Forrester is recommending cautious IT directors to investigate alternative push e-mail technologies such as Microsoft's and line up "priority users" to migrate.