Thanks for your reply on that matter. What I did not want to say is, that ETA will always be a better option beneath a small batch, high developed craftsman brand like P. Dufour (where a few watches will be one years salary for the watchmaker) or on the other "side" decades of engineering like Rolex or AP for instance. 

In short and further related to the always lurking "Whaat, 1000+ currency for an ETA caliber?!":

Take "In-house manufacturing caliber" just not as an always applied justification for quality and reliance. 

But that could be a never ending discussion, because most of us will never know and the trends are ever changing.

And because I am starting to sound like the self claimed experts: this is my opinion, based on research online, reading on some encyclopedia, videos and my perception of all that.

In most cases in house manufacture calibers will use non patent (old) developments by ETA or any other proven design. Not to mention, who is the true supplier for the parts. There isn't much transparency with a lot of brands. So you never know what you really get. Alas ETA off the shelf could get you sometimes higher reliability and future proof service over a truly "own" design. 

My wife does buy quite a lot fountain pens and other stationary stuff. So we have some kind of "its your own money" thing. We both know its sometimes buying things you want, but don't need.