Some people report great accuracy from some Mosins. I've seen Marlins shoot some really nice groups with the right ammo (LeveRevolution really does shoot well).
Which would I rather have?
What for?
The Mosin carbine is nasty to shoot, but handy enough though a lot heavier than the Marlin. The rifle is a looong gun, not handy at all, but more pleasant to shoot. The Marlin is a handy lever rifle that has stood the test of time and still sells well, new, after it and its antecedents have been produced for over 110 years.
Neither gun would be my choice for a scoped rifle.
All told, I'd take the Marlin with iron sights (maybe Skinners), and neither gun with a scope. But that's because I want a handy hunting rifle.
(If I wanted a scoped long-range bolt gun, it wouldn't be the Mosin.)