its a shitty show.
if u just wanna see fanservice check this compilation - http://fapservice.com/gokukoku-brynhil...mpilation/

This show doesn't have too many fanservices (it's only one scene as I remember), on the contrary it gives many guro scenes. Like body melting, blood, etc.

If you don't like those scenes, I think you don't want to watch.

I think the only fanservice is in episode 5, onsen's scene. Again, it's based on TV version, I don't know if there's additional fanservice scenes in Bluray version.

For the story wise, apart from that "not for weak heart" scenes (to be honest I couldn't bear much when it comes for scenes like that too), the story itself quite proper, it has some conflicting/problem plots, unique characters' abilities, and the ending that somehow answer those problems plots.

You should try first episode first , and then use the impressions after watching first episode whether you should continue to watch it or not. :)

(I even "correctly" did not watch School Days, because, after skimming first episode, I just feel something was wrong, so I skimmed the last episode, in the end, it's "Nice Boat", hahahaha, thankfully I didn't watch that :D )