I remember the two previous models which were too big, though very interesting and I prefered the PLM Tourbillon version (especially because of the opening/closing hour window).
However, knowing that it is now 40mm and that I like the jumping second feature, I think it is finally a watch I would like to have a much closer look at.
The only thing I don't like is the power reserve reminder though. I like the indicator on the Dato U/D or the new Dato Tourbillon but not on this one. I don't know, maybe the shape and the classical look (versus sportier for a Dato).
The Constant force is another great feature of this watch and I like when things are done in a coherent way.
Thanks a lot for the great review Fx 
Cheers, Mark