For a moose rifle, I would absolutely choose the 3.5X10--I might even consider a 2.5X8. Moose are large enough that the extra power is not necessary at 400 yards. On the other hand, I can easily imagine circumstances where 3.5 power was way too much for running shots in thick country at close range. If this was to primarily be a deer rifle where long shots were the norm, I probably would go with the 4.5X14. By the way, I nearly purcased the identical set up this year--nice choice ( I ended up finding a killer deal on a used but mint Mark V).