To be more precise, I think that Girard Perregaux took their inspiration from a Rolex project born in the late 90's, called ELF Project, to make their Constant Escapement: 

( Credit unknown: I will happily credit on request ). 

Nevertheless, in 2013, this watch was quite revolutionary. It first came in a 48 mm case. Then, in 2015, in a 46 mm case, in white gold or in Black Carbon Titanium ( 2017, if my memory serves me well ).

The first Constant Escapement, from 2013. 

Then, the " smaller " ones: 

The three  altogether: 

So, this year, Girard Perregaux totally revisited the Constant Escapement, more aesthetically than mechanically. Mechanically, you have one more day of power reserve 7 Days, now ) and 14 components have been removed ( 266, now ). Another important detail, it is a Chronometer, now. 

Aesthetically, the case has the good taste to be smaller ( 1 mm smaller, to be precise ) with a diameter of 45 mm. But it is not thinner... 14, 2 mm for the original, 14, 8 mm for the new one. The good thing is that it is made of titanium, which will be excellent for comfort, compared to the former ones in precious metal. 

The dial has been totally revisited. Ok, you see the typical Constant Escapement design and you are not disoriented, but now, the legibility is better with time being displayed in a more classic way rather than in a small sub dial. And, last but not least, you will find with pleasure the superb and very modern " Neo Bridges " which I like a lot. 

To give you a better idea, a comparative photo of the former and the current Neo Constant Escapement: 

I think that here, Girard Perregaux goes farther by associating the aesthetics of the Neo and the concept of Constant Escapement. Simpler said, this association makes this watch look even more " conceptual ". 

Now, there are two things I regret: The price increase, which is consequent, even more when you compare this one in titanium to the former ones in gold... And the fact that I would have loved to see  a tad smaller version, in 44 or even better, 43 mm, which is possible due to the movement dimensions ( 39, 5 mm ). While we are at it, a tad thinner, too. 13 mm would be perfect, due to the fact that the movement is 7, 40 mm high.

But, as it is, despite these small reserves, I love this Neo Constant Escapement and would dream to own one, one day. 

Looking forward to reading your comments and thoughts,

Best.

Nicolas