Son's first Rolex, GMT II or Sub no date?

[PeterT]

Hi,
My eldest son is contemplating buying his first Rolex but is quite impulsive. At the moment he is wanting the Sub no date as it is the most affordable sports model.
I know that he likes my GMT II Coke but that model would only be available pre owned.
He is very knowledgeable about all of the sports models and so is fully aware of all of the good and not so good bits on the various models.

He will probably end up as a teacher and so the date function would be useful and the GMT has the extra interesting complication.
If times became hard which would be the easiet to sell and which would return more of his money?
He really wants a brand new watch which is the other factor pulling him towards the Sub no date. The Sub date is available new as another option. He is not keen on the LV green bezel.
I have told him that unworn or excellent GMT watches do appear for sale.
If it were me buying it I would go for the SeaDweller, it has the date, no cyclops, very robust and not as common as the Submariner series. Only problem is that the SD is more expensive again.
Looking to the long term which do you think would be the best watch for him.

Thanks for you thoughts.

PeterT