Can't speak much for the really high end machines, but here is my experience:
Bought one several years ago from Goodwill, wanted to make pesto with it mostly. Worked okay, I found I didn't much care for it for other stuff, seemed more trouble than it was worth. used it to shred cheese and other vegetables, made a mess but it was fast. For some reason, I thought buying a "more modern" one was a good move, so got a Black and Decker, it was certainly less beat up, but didn't work any better than the Goodwill one.
Bottom line, I still pull one or the other out once a year to make pesto, maybe shred mozzerella once in a while, but unless you got one of them there dishwashing machines, they are a pain to clean all those parts.
Someone gave me one of those blending/chopper sets like the ones on the TV infomercials (Magic Bullet or something), and I use that a lot more.
I am with Delta and DevilsBrew, buy one of those Ninjas. But first, get her a CHEAP food processor to see if she likes it.
Another option--a little more pricey but more versatile, a Kitchenaid stand mixer, you can get attachments for it.