I heard of them, the older albums are reported to be really sick, but I never listened to anything of them. And the new album is crap, as far as I know.

But you should really try Eisregen's "Krebskolonie" (cancer colony). "Leichenlager" is also a morbid masterpiece, although it is less "black metal". I haven't listened to the new one "Farbenfinsternis" yet, but I think I'll buy it soon.