BlackBerry is known to have solid security and was the go-to device for the U.S. government before the rise of the iPhone
As I remember it was found that while there was some authentication, they didn't exactly encrypt the data between the carrier and the account. So all those messages are in the free and clear if you can intercept.
However, not pretending to be an expert on that. It's just that the "more secure" is an old impression and BlackBerry hasn't made as many changes as the iPhone.
But to be honest, there are a lot of features now that would make ANY smart phone a security risk. Does anyone in the Secret Service not read up on all the security services now competing with devices to legally spy on everyone in a given zone? They advertise equipment that you can walk into an airport and be scanning everyone's phone and wiFi traffic in a minute.
So the "illusion" of security might be intact with BlackBerry, because nobody is talking about it anymore. They "talk" about security issues with a major phone like the iPhone because;
1) More features means more points of failure (possibly).
2) The security company needs fear, uncertainty and doubt to be relevant. Sending out warnings is a way for them to look like they are on top of things.
3) FUD is paid for by competitors.
They should be talking to the CIA and NSA for what those guys think on security. Likely Obama needs to have an assistant with a "burner phone." He's just looking for a reason to stay with a device he likes to use (and not change), but security is really a bad excuse -- there is none. All these devices have GPS built in unless you physically disable it -- and it's there whether YOU use it or not.