I have invaders in a 171 and lizzies.  Believe me, the Lizzie are unbelievably soft.  And as far as all mountain, they are good until it gets chopped up.  You go through anything that is tracked out, not fresh, or not everyday groomer snow, you will be taken for a ride.  I have ridden my invaders through chop and hauled ass.  With the Lizzies, you have to be on top of yourself or you will be taken for a ride.  The softness makes them bounce everywhere in the chop.
The flex pattern is definitely different too.  Super soft in the tip, a little stiffer in the tail, unlike the invader which is just soft all over.  Here is any easy way to compare them, I can do tip stands on my invaders, when I try on the lizzies, they flex so much that the tip doesn't dig into the snow, the ski just completely bends and the base of the tip is still on the snow.  Maybe that wasn't a good comparison.