all of these other apps like Kik and Whatsapp requires all parties to have the app installed on their phone to work. i don't see them as true replacements for BBM. I can't imagine asking my business contacts to install an app. on their phone so I can IM them. It's a bit intrusive and some companies lock down their BB users so nothing can be installed on the phones. What then?
I'm with Notorious...
Good on RIM to have an app that is exclusive to themselves to keep the market share. For this very reason I can't see myself moving off BB to another device. BBM is just too useful to give up. Too bad they'll never catch up to Apple in the app space and UI.