As a former 415M owner, I completely agree with Loudthud's assessment. It's a cool cabinet with all those 15s but it just didn't have the warm sound of my older 215 cabs - that's why I'm a former owner.
CLD
And you wouldn't need a four man crew and a derrick operator to load in & out!!
(I have to believe that a 4 X 15 is one Heavy, Bulky monster to haul around, although in theory, I love the idea of a 4 X 15 designed for Bass, maybe for a static situation, like for at home or the practice space....you never have to move it kind of situation).