One brand is the argument. The other is the proof. The problem is deciding which is which - and the answer tells you more about yourself than about either watch.
Patek Philippe makes the case for itself loudly through silence. The advertising says nothing. The watches say everything. The Calatrava is so restrained it becomes a provocation - this is what taste looks like, it says, and if you don’t see it, that is your problem.
Vacheron Constantin makes a different argument. It is the oldest continuously operating watch manufacture in the world, a fact it mentions with the frequency of a man who knows it is his strongest point. The Overseas is mirror-polished on surfaces you will never see unless you remove the bracelet. That gap - the polish that exists for no one - is the whole case for Vacheron.
The question is not which is better. The question is which argument you find more convincing.
Patek says: we made the watch the room agrees on. Vacheron says: we made the watch the room doesn’t need to agree on. Both are correct. One requires the room.
The Calatrava ref. 5196 is a more perfect object than the Overseas ref. 42042. It is also a less interesting one. Perfection, achieved too completely, becomes a kind of silence. The Overseas has a flaw - the integrated bracelet is not quite right, the proportions argue with themselves slightly - and that argument is what makes it alive.
Vacheron wins on machine. Patek wins on claim. Which matters more depends entirely on why you are buying a watch.
If you are buying it to be understood, buy Patek. If you are buying it to understand something, buy Vacheron.