The main reason a business goes with Blackberry is secure email.
Countries like the UAE and Saudi Arabia had confronted RIM to get them access to the servers in order to snoop on their people. That right there tells you about how secure the system is.
I am not sure I would own a Blackberry as a personal device (or any smartphone for that matter), but as a business device, security is everything, or you risk theft of your data/emails and intellectual property.
In the real world employees are using more Androids and iPhones than BBY for email.
I highly doubt that sending an email through my phone is that much more/less secure than from my computer.
There is also the matter of mobile banking.
Once again, I don't know but I highly doubt that my phone is any more or less secure doing it than if I continued to use my BBY or if I used my laptop.
IOW, I suspect that BBY claims have little value in a world where security seems to be good enough and people are going to use their devices for what they want anyway.
This is why RIM is not going to be around much longer - they cannot rely on the paranoid sky-is-falling crowd to buy their phones in sufficient numbers. Especially since BBY gives the information to any government that asks.
These crazies don't like that at all.