Use your scoped 300 on lion and large plains game, get the(iron sight)450NE double for everything else.
I also have a Sabatti double in 450NE and it is a GREAT rifle. I paid $4900 for it New in the box and it is as well built as my name brand british double. I think that they really are "undervalued" or more likely, the others are just seriously "overvalued"!