If I had to pick between those two I would go for the Marlin. But with that much cash to spend I would try to find an older gun like your son has.
I like the new Marlins but the laminated stock and thick wood on the forend doesn't make me happy. I do like the ballard rifling and the 1/12 twist of the new guns. I wish it would occur to Marlin to put that same barrel on the blued models.