Hi there,
I cannot really make up my mind on this model - or the white dial one.
Hopefully, I will have the chance to look at both side by side in a few days.
Right now, I feel its more safe to go for the classic white dial in my personal case - IF buying this thing. 
When I got "into" JLC watches some 15 years ago - one of my favourites was the Master Calendar - together with the Master Date.
Both a tad too small for my chubby wrists, being 37mm. (If I am remembering correctly..., not sure, getting old)
Now, here we have the new 39mm versions...
Still, I personally would have preferred 41-42mm, but interesting indeed!
Thanks for bringing up this model,
All best
Bent