I'm failing to see how people think that iMessage is anywhere to close to dedicated IM's. I get that people prefer iMessage because all their friends are all on iOS/OS X or they don't need anything than simple messaging but that does not change the fact that when compared to other IM's, iMessage is not even close and it's even laughable that people are really taking a hard stand that iMessage is up there.
Can iMessage be great? Absolutely because Apple has iChat/FaceTime and a great platform to combine. But iMessage in it's current state, it really is nothing more than SMS with blue bubbles.
What I also find amusing is that when BBM finally came to iOS and Android, everyone was laughing and saying it won't be successful because no one is using it or everyone is on Whatsapp. But now, they're willing to jump and try even lesser IM's with even less users. Nothing against them, use what you want but I laugh when I remember all those BS responses. People are really brand whores.