Debian Unstable vs. Ubuntu

[Rami Kayyali]

This might be a bit of an odd subject, I know they're both Debian, but
I still don't know what exactly are the differences between installing
either Debian Unstable (Sarge) and Ubuntu, so could you please give me
some highlights? Are there any reasons to installing Ubuntu rather
than Sarge or even Sid, since they both provide up-to-date packages,
so what's the difference?

Thanks a lot in advance.
Rami Kayyali.