I don't know too much about the relative security chops of different smartphones, however in terms of what's actually in this article it seems reasonable for the government department to consider the iphone a security issue within the context where it presents this particular problem and for the reason why it presents that problem for them. However, it does also seem like the very reason this is a security concern in this more narrow context is arguably a better security option in almost every other context so I wonder if that's what they were getting at with the scare quotes.

In the case of defence personnel entering secure locations they say the iphone represents a threat because it doesn't allow 3rd party apps to control inherent functions of the device, so the defence force cannot use an app they developed which would presumably do things like disable all voice recording abilities so they can be sure that people walking around secure locations aren't unknowingly or deliberately transmitting or recording conversations and sensitive information. I can see why this would be a problem for them, however if you don't work in defence and are an average consumer, the fact that random 3rd party developers can not do exactly what such an app would be designed to prevent sounds like a more secure way to operate. In that scenario, apps are incapable of controlling inherent functions of the phone unless they're developed by Apple. Obviously this leaves the door just as open for untrustworthy behaviour from Apple themselves, but if you've chosen to trust them, you can at least be sure that no one else is controlling your device in ways you wouldn't want, unless the device is somehow hacked but in that case, well it really doesn't matter which phone it is because somehow it's security has been circumvented and at that point all bets are off.