Uses data instead of SMS
No character limit
Can set status/ busy messages
Can see when BBM is Delivered and Read
International use
Can send/save Voice Notes
Can send/save Pictures
Can save chats
Can copy/email chat
Posted from my CrackBerry at wapforums.crackberry.com
No a person's mobile number is different from their PIN number.
Sending messages by mobile number will cost you, PIN messages do not if you have a data plan.
You can tell if the person is offline (phone off or out of service area).
There was another feature that I really like and I'm not sure why it's gone after the official update was if someone is on a phone call then the person's status would change to as busy on a call. I hope this feature comes back on future updates.
SMS can run into all kinds of weird delays pretty frequently too...
You can have sending issues on your side, or receiving issues on the other persons carrier server, etc.
I've had it happen many times where someone gets a batch of my messages the next day or several hours later for no reason, even though they supposedly sent fine on my end.
I like it because it saves me 10 dollars a months on a texting package. Most of my close friends have BBs and so we use BBM. I get by with just 500 texts a months that way!