So just from snooping around the internet it looks like the Rossi Scratch is an advanced level park ski that they put all their competition skiers on for X Games type stuff (i.e. probably stiff) while the Volkl Alley seems to be more of a beginner, soft park ski.
If you're looking for a beginner park ski that will help you butter and won't be a huge jump / pipe ski I would go with the Volkl Alley.