You make a lot of generalizations. You said it is lightning fast. This is not true compared to XP. You said it is better than XP. And this is only partly true.

Yes, Vista has some improvements but it also is bloated and because of this sometimes slower than XP. And there are compatibility issues. Most companies still use XP because of this. I also run XP in a virtual environment because of this. I would rather use only one OS.

So it is definitely not better than XP in all terms, but some interface and security improvements are better.