It's bad anime. It is below averange level for grown-up people.
I didin't read the manga, I don't know how's with it, but this anime is bad. If you haven't watched it, you can of course but I tell you - go with some other series with high rating. You won't waste a day of your life this way.
I don't know what do people that claims it to be 10/10 see in it, maybe it's because they loved the manga or they watched it in school and feel a sentiment.
Well I didn't read it and I'm not in schoolage, and here's how it looks for me:
Good thing in it for me at least is medieval setting, knights, kings, castles and all - wich can be in some degree enjoyable.
Now bad things:
It's not so easy to stand the old-fashioned art and poor animation it has but it's somehow understandable as this series has its years (although it's not SO old). Anyway it could be not a flaw if the plot and the feeling were good. (or awesome like in Cowboy Beebop)
But the story is infantile. The unvincible hero with posture of a bodybuilder, silly and kind of funny combat scenes, flat dialogues, not much of depth - what's this? He-man? Teenage Mutant Ninja Turtles? I bet I would be enjoing this like hell... if I was 10 years old. I would write in this review it's kind of cartoon for kids and if you're a teenager go ahead and watch it but what with all this bloody violence and the final rape scene? Then for who this anime is except Berserk manga fans? It's just poor.
I could count many examples of its silliness but take this one. What's with this name of the main character - Guts? Give me a break. With his posture and overall macho image in anime it would've been good if this series were mentioned to be humorous. But it attempts to be serious. And he's running, swinging his big sword, defeating countless groups of enemies by himself. Again - stuff for kids. If there were some humorous thing about it, some wink or just another interesting things in this anime it could've been different. But there's no such thing!
Opening theme is silly for my taste so my personal sound raiting goes down a little too.
In summary it can be a little entertaining but it absolutely can't be compared to other high rated anime like Samurai Champloo, Cowboy Beebop, Genshiken or whatsoever, you get the point. It doesn't deserve even 8/10 and it's for sure no masterpiece.