A few thoughts: By the director's own admission, this movie was made for the sole purpose of shocking people and defying censorship. As a proponent of free speech and anti-censorship, I do have to wonder if "just because" is enough of a reason for something to be made. This entire movie is basically a lose narrative centered on a guy who likes to disembowel corpses (collecting all their bits and pieces in jars, of course) and have sex with them -- the corpses, I mean, not the bits and pieces. Aaaand that's just about it. If you want to watch a collection of gross-out scenes that serve no purpose other than to be gross, well I've got the movie for you! If you think it would be fun to watch someone stab themselves in the stomach while ejaculating and bleeding out of a fake dick spliced with footage of someone field-dressing a rabbit, I can think of no other movie that could satisfy you quite like Nekromantik. As for me, I don't see the point in this movie, even though it's a supposed classic of the exploitation genre.
Who would I recommend it to? I dunno. Murder-perverts, maybe? You'd already know by now if you wanted to see it.