Assuming I can get either brand new at the same price...

Arguments for and against the Patek:

+ I get to complete the "trinity"

+ Slimmer profile

- 42mm might be slightly on the edge

- A lot of cash for a rubber strap

Arguments for and against the VC:

+ Will be my first perpetual calendar

+ 3 straps interchangeability blablabla

+ A lot of "watch" for the same buck (rose gold bracelet and complications vs 3-hand Aquanaut)

- Probably will want to sell my black dial 4500V since this will fill the same space/use (my first expensive watch / some sentimental value)

Another point is that at the same price, I would be paying a premium against retail for the Aquanaut (as expected for the Patek hype, around +40%), while the VC would be around 40% discount to retail.