ive ridden both, heres what i found:
scratch fs: better in bumps, lighter, quicker, softer, and carving off jumps. not as good at high speeds, landing bigger jumps, or riding pow.
fujative: more consistant wood core, stable, durable, poppy, better in pipe. the fujative is a bit heavier, not as good at carving, a little sluggish edge to edge.
all in all they're both great skis for somebody who is going to ski 60% park/40% mountain.
if you weigh less than 160lbs, i'd go with the rossi, unless you really destroy skis. if you weigh more than 160lbs, i'd recommend the k2.