Well, if S.O.D. are obscure or not it's a matter of the year one was born. In the late 80's was very publicited, because it was a side project of two Anthrax components, Spitz & Benante (and Lilker, who played bass in Fist full). And Anthrax were great in that times.
For S.O.D. itself, was very funny, but not great musically. But it changed a lot of things in the crossover area, and that's the reason many people consider it a classic.
Wsx26, if you like S.O.D., you can try M.O.D. (Method Of Destruction), Milano's band in which he tries to follow S.O.D. path.
<a class="postlink" href="http://es.youtube.com/watch?v=_B5DKyT_FqY">http://es.youtube.com/watch?v=_B5DKyT_FqY</a>
(hey, and M.O.D. is really an obscure thrash band 🙂 )