Use vBulletin 2 instead of vBulletin 3?

[AlexndR]

Hello. I know that vBulletin has more features than vBulletin 2, but do you think there is any reason to use vBulletin 2 instead? Because some people still use vBulletin 2.

I also wonder if there is a karma/rating system for vBulletin 2 and some other features that vBulletin has. Also if there is a multiquote system for vBulletin 2, do still some people develop for vBulletin 2? How is the theming vBulletin 2 vs vBulletin 3? Maybe there is also AJAX plugins for vBulletin 2.

And why would you use vBulletin 3.0.x over vBulletin 3.6.x? or vBulletin 3.5.x over vBulletin 3.6.x?

Is there a vBulletin 3 theme available for vBulletin 2?

EDIT: I of course mean use vBulletin 2 over vBulletin 3. Can't edit title.