There are so many people out there who don't know about anime. These are the people who usually say that "if it's animated, it must be for kids." To those people, I recommend you watch Berserk - just be prepared.
Although there are many anime out there with lots of blood and violence, I can only think of one or two off the top of my head that even come close to the trials of Guts. Yes, the protagonist's name is Guts. That should give you an idea, right off the top, what you're in for. Be ready to see a lot of blood, and dismemberment, and beheadings. What I found astounding is that the director did such a great job at keeping the bloody and grotesque themes, but still toning it down from what is portrayed in the manga (I kid you not!).
The opening of the series gives the viewer the impression that this series will be about a disgruntled man who has honed his body to kill demon apostles. What we soon learn is that this is the end of the story, and we venture back to how Guts became the Black Swordsman - a warrior of mythological proportions. We learn how he lived his life as part of the legendary Band of the Hawk, under Griffith, one of the most charismatic characters I've ever watched.
As the story continues (and I will do my best not to give anything away) you can almost forget what you've seen at the beginning as Guts is developing bonds, succeeding in battles, and becoming a legend. It makes the fall at the end all the more poignant.
Anyhow, loved it, reading the manga, and already 24 volumes (yes, VOLUMES, not chapters) in. Kentaro Muira, you are genius.