> Apple iMessage, can't inter-operate between Apple and Android devices (very stupid tactic, it will get marginalized).
Apple's iMessage works fine with Android in the western developed world where you can get unlimited/cheap SMS. Also android support won't help iMessage in markets like India where there are very very many feature (j2me) phones out there.
Apple and WhatsApp have different goals. FB is far more threatened by WhatsApp than Apple.
What's at question here is whether you think the emerging market telecom providers will ever see their doom and lower SMS pricing before WhatsApp, Viber and the like remove all their messaging income.