I find it interesting this hasn't gotten as much attention as other announcements. It seems to hand over a great deal of responsibility to Apple, at least in terms of performance. Something some might feel comfortable with or not. I can imagine this lack of control about what instructions will actually run on the hardware might not fair well with some developers?
As for Android, having ART on the phone is technicality, given the platform fragmentation Google rather leaves to the OEMs the task of making ART generating the proper code.
