Welcome to MO! I have a Redfield Revolution 2-7X33mm scope on my 308MX and it works very well. This Redfield is made by Leupold and has the same quality and guarentee. Basically the scope is a Leupold VX1 that costs about 30-40 bucks less.
I put a Leupold VX-3 2.5-8x36 on my 338mx. Having Leupold install a CDS dial for me also. I have no qualms about shooting it 450 yards unless it is real windy. Range it, dial it, hold dead on, kill it. But first....I gotta find it.....
Lot's of good recommendations before me here. Something you may wish to consider is scope profile and the handling of your Marlin. A smaller profile lends to preserving the great handling of a Lever rifle.
I have both the 2007 JM 308MX and 2008 JM 338MX. The later had a scope on it when I purchased it, a 3-9X40. I find the profile does take away from the handling of the rifle. I put a 2-7X33mm Redfield Revolution Accurange scope on my 308MX and it made a very large difference in retaining the great handling.
At the distances you are looking at the 2-7X33mm would be my choice. I have a self imposed limit of 300YDS and the magnification is plenty enough.
To give you an idea of scope profile between the two I'll attach pictures for the comparison. The 338MX is getting a new scope soon in 2-7X33mm.