The update should be available to all users now. Surprisingly, it's still running Android 4.0.3, and Face Unlock is still seemingly absent. It's possible that there was a bit of misinterpretation, since the original changelog was translated from Italian to English and ASUS actually stated that it was working on Face Unlock, not that it would actually be available in this update.
One thing it does bring, however, is something that Prime owners have been missing since the beginning: battery information, so you can finally see what has been chomping away at your precious juice. You can also check notifications without unlocking the device now, which is quite handy.