Like a lot of other people, I'm giving this manga a ten. It's more or less perfect in the sense that it flawlessly executes what it's intended to do. HOWEVER. It's not for everyone. There is some SERIOUSLY sick and twisted stuff inside. If you go in fully prepared to witness what comes close to the darkest depths of the human capacity for depravity and cruelty, you'll see a masterpiece. If not, you'll see something you'll legitimately wish you hadn't. I know a few people who regret reading it due to the trauma of what goes on at points.

As a side note, I've seen 300+ anime to completion and read so many manga I didn't bother putting them down in my MAL profile. Out of all of them, I haven't found a villain even half as vile and compelling as Berserk's antagonist. I suppose Johan from Monster comes close, but I can't think of anyone who tops the monster in Berserk. The author is notorious for taking long hiatuses, often due to health issues, so the thought that the series might end before completion without the bad guy getting what's coming to him is borderline infuriating.