from my understanding the Pro One GMT is not a true GMT......while the movement does have a 24 hour hand modification, neither hand is independent......meaning that the watch works the same as the now discontinued Rolex GMT (be it the 1675, 16750 or what ever).......the 24 hour hand simply shows the same time as the 12 hour hand (but in 24h format).
While I applaud the fact that Chopard has chosen to release a newer version of the Pro One I think it's shortcomings should be noted..
As well, on another note, Blancpain was the first company to release a diver's watch with a bezel cover in sapphire...specifically the Anniversary Edition of the Fifty Fathoms (Series 1, 2 and 3 IIRC).
Don't get me wrong, I love Chopard and I was one of the first owners of the Pro One way back in 2002........but let's not get taken in by the Chopard marketing...........there are many other "true" GMT watches out at the moment that would suit his needs.......and still have a similar horological cache.
Cheers,
jdm