Do you mind providing examples of use cases re Google Now vs Siri? Not disagreeing with you - just haven't owned an Android device in the last year to know.
https://itunes.apple.com/us/app/id284815942?mt=8
At least I think that's Google Now. It looks similar though maybe it's missing some features?
Of course with it not being integrated into the experience it's not quite the same. (can't appear on your home screen etc...)
3 Months ago http://www.youtube.com/watch?v=bohfoK-edfU