Submit bug reports to Debian or upstream project?

[Glen Pfeiffer <glen@thepfeiffers.net>]

Is it preferable to submit a bug report to Debian or to the 
upstream project? Assume it is not a Debian only package, like 
GNOME for example.

I have searched for the answer and found This:

	http://www.debian.org/Bugs/Reporting
	_If you file a bug in Debian, don't send a copy to the 
	upstream software maintainers yourself, as it is possible 
	that the bug exists only in Debian. If necessary, the 
	maintainer of the package will forward the bug upstream._

That does not tell me if it is preferable to submit it to Debian 
or upstream.

-- 
Glen