Just a quick update, my local AD (in the UK) recieved one in today.
It really is stunning in person, the face colour is as vibrant as the 'on the wrist' pictures here, but the glass is just fantastic, hopefully something they'll use in more 're-issue styles' in the future.
The sapphire caseback seems almost identical so still not certain on the merits of the 'glass box encased mechanism', it did seem slightly lighter than the standard 39mm Carrera, but think it may have just been my imagination.