No arguments there. But I suppose if you want a tooltip framework that also bizarrely functions as modal dialogs, hover menus, alerts, notifications, ........., and maybe even tooltips, qtip2 would probably cover your bases.
It also doesn't really look fine. The shadow doesn't follow the pointy bit, which looks especially bad with such a huge drop shadow. Does this even work across browsers?
There are a bunch of ways to do this already, and this requires jQuery. The only way I could see this as being interesting is if it has no dependencies. I really wish people would stop developing with jQuery as a dependency...
e.g. Bootstrap's popover: http://twitter.github.com/bootstrap/javascript.html#popovers