One of iOS 5's most anticipated features is iMessage, an Apple instant-messaging service that can be used only among iOS devices. This is essentially Apple's answer to BlackBerry Messenger, RIM's own internal messaging system. The idea behind both messaging services is that they don't cost anything extra and won't deduct from your text messaging plan.
BBM is for those who like the multitude of features and settings that complexity brings. However, it has quite a barrier to entry. It uses a separate app, and with that, a completely separate ecosystem from normal text messaging. You have to request contacts to be added to your list, and there are a number of ways to be added: e-mail, PIN, or bar code scanning.
iMessage, on the other hand, is built into the existing messaging structure. You won't even know you're sending an iMessage until the phone automatically detects that your recipient has it, too. The barrier to entry is thus extremely low; if you know how to text, you know how to iMessage. iMessage can also be used across all iOS devices and not just the phone; you can start a message on one and finish it on another.
BBM is for those who like the multitude of features and settings that complexity brings. However, it has quite a barrier to entry. It uses a separate app, and with that, a completely separate ecosystem from normal text messaging. You have to request contacts to be added to your list, and there are a number of ways to be added: e-mail, PIN, or bar code scanning.
iMessage, on the other hand, is built into the existing messaging structure. You won't even know you're sending an iMessage until the phone automatically detects that your recipient has it, too. The barrier to entry is thus extremely low; if you know how to text, you know how to iMessage. iMessage can also be used across all iOS devices and not just the phone; you can start a message on one and finish it on another.
Source:
http://reviews.cnet.com/8301-19512_7-20120646-233/blackberry-messenger-vs-apples-imessage/?tag=TOCmoreStories.0
