iOS and Android don't even come close when it comes to security.
That's why there are still companies (that have very secure environments) that only allow Blackberries.
There's also the bandwidth issues. Email on an iPhone or Android can easly use 10x as much bandwidth as a Blackberry. My old BB 8900 with a slow CPU and a slow "edge" connection, can usually open an attached TIF or PDF from our exchange server faster than a current generation iphone or Android.
For people who don't understand how that's possible, it's due to the Blackberry Enterprise server. With an iPhone or Android phone, you have to download the full attachment, and then open it locally on your phone (assuming your phone can even open the attachment). With a Blackberry connected to a BB Enterprise server (free for small businesses by the way), the attachment is opened on the server, and just a scaled version of the attachment is sent to the phone.
Yeas but you forgot the most important part...BES SUCKS! I hate managing that thing...