I don't see anybody ditching RIM yet. Security needs to be proven with a track record. No matter what systems they deploy, there will always be exploits and hacks.
There are quite a few companies using iPads as well (SAP for example bought 3,000+ for their sales workforce)
Then you haven't been reading asymco :).
This recent article includes such sentences as "During the last month alone RIM lost 1.2 million users." http://www.asymco.com/2011/10/07/3411/
In the context of the article, by "anybody" I meant companies and organisations, who are working with highly sensitive and confidential information. That's the segment the phone in the article is trying to compete in. In order to move these people away from RIM, they have to build up trust though, which is a long process.