Pure opinion
Kind of cool, but could be done without. I wouldn't use it.
These systems are a bit flawed unless you have it heavily trained. ie. you say something, it thinks you said something else.
I havn't used it, but 5 times? Doubtful. Maybe 2. But, honestly, I can't see a newer OS being faster than than fully developed older one. I'd say it depends on computer speed more than anything. I've got XP, it's insanely fast right now. I can't see faster making much of a difference.