First, I should mention that the manga is one of the best in terms of quality with highly elaborated graphics that are incredibly detailed, written and illustrated by Kentaro Miura. Very few artists can create something like this and this is perhaps one of the greatest challenges the animators face in order to create a faithful adaptation to the source material.

The manga is currently the best medium to enjoy this story, however, I'm an anime fan, Berserk Manga is the only manga that I have ever attempted to read and after several years I'm still in chapter 1, despite liking the story and the art so much. Manga is just not the ideal medium for me, it can't keep my attention the same as a good anime does.

For this first series, they use a minimalistic approach, it still retains the layouts and recognizable panels from the manga, but not as much detail. I find it surprising how well it has aged considering how old it is. It belongs to the 3-year-anime-boom when some of the best, and most enduring shows were created.

• Skip Episode 01 - This episode is part of the next arc (Black Swordsman Arc) and is the same as Episode 01 from the 2016 Sequel, so you won't be missing anything. The one from the 1997 series is not a good introduction for what you'll see on this arc (Golden Age). Furthermore, it fails to introduce an important character and since is the only episode from the Black Swordsman Arc, it feels out of place, not being relevant to the story of this season.
• Watch Episodes 02 to 20
• Optional Episodes 21 to 25 - The story on these episodes is covered more extensively in the third movie Berserk: Golden Age Arc III - The Advent. However, these episodes show slightly different content but not as much in-depth as in the movie, they fail to introduce an important character and they are quite rushed in the ending. I would still recommend watching both this version and the movie (as there are some parts that are done better on this version and things are explained better, including Griffith's reasoning for how he comes to a decision at the end), but if you just want to continue with the main story, then jump to the movie.
• Alternatively, you can just watch this season to the end and then jump 52 minutes into the 3rd movie, Berserk: Golden Age Arc III - The Advent, at the start of the Eclipse, so you can watch both versions. Despite the old style, the graphics & characters are much better in the 1997 version and way more memorable than in the movie.

Why You Should Watch/Read: Berserk? (It contains some spoilers in order to explain the why so only watch this video if you are really hesitating about starting this show and pay attention when they say you should skip the video in order to avoid anything major)

"After finishing Berserk, I had to take a moment and reflect on what I had just experienced. To put it bluntly, this series is deep and complex, which is something that surprised me. I didn't expect that at all going into it. I suppose I wasn't sure what I expected. But subtle layers with timeless messages?

Without offering spoilers, the method in which this tragic tale is unfolded is itself a testament to storytelling. It is executed carefully and methodically, as is the development of the characters, whose motivations are easily real enough to draw empathy from any viewer. In fact, that's probably the aspect that astounded me the most; each character had solid reasoning for who they were and that made the tragedy's finality all the more sobering.

If you're hoping to watch Berserk to experience copious amounts of gore, you're missing the point. This is a story with a message. In fact, several messages. And the messages are as poignant as they are sobering.

tl;dr - Berserk is one of the best anime series ever made." -Phaxuji

Literary References:

Except for Femto, all of The God Hand's antagonists names, have literary references:

• Void's name is borrowed from Frank Herbert's Destination: Void.
• Slan's name is borrowed from A. E. van Vogt's Slan.
• Ubik's name is borrowed from Philip K. Dick's Ubik.
• Conrad's name is borrowed from Roger Zelazny's ...And Call Me Conrad.

The dub is excellent!

Skip on First Watch, is better to see this movie when you want to rewatch the series.

For these movies, the animation style has changed to a combination of regular animation & CGI and is quite good for being CGI, but not as good as hand-drawn shows.

This movie condenses Episodes 02-10 of the 1997 Series and as you can imagine, it feels extremely rushed, missing some of the best parts of the show. However, it does have some extra scenes not present in the 1997 version and even when the content is the same, it seems to present it from a slightly different perspective, there are less censoring of both gore & sexual scenes, including rape. They also animate the action instead of just panning static images.

The dub is good.

Skip on First Watch, is better to see this movie when you want to rewatch the series.

This movie condenses the events of Episodes 11-20 from the 1997 series. I prefer the story as it's presented in the 1997 version but this new take on the animation is worth it when rewatching the series.

The dub is good.

Watch.

This is the equivalent of the last 5 episodes of the 1997 series, but it goes further into the story, currently serving as the best bridge between the 'Golden Age' and the 'Black Swordsman' arcs.

The dub is good.

Optional.

• This is a TV Editing of the original Golden Age Arc Movies, but I will still recommend you watch the movies if possible since breaking down the plot into episodes disrupts the pacing. However, they are not that different, so if this is what you have available, then that will be ok.
• The additions made to the TV version are minimal and often unnecessary. Some scenes try to explain things better, but the execution is poor.
• Berserk 1997 remains the best for telling the story. These were made for people who were already familiar with the story. So if this is your first time watching, then I definitely recommend you make an effort in watching the 1997 version, after all, you can only watch something for the first time once.

Watch. Continuation of the story.

These sequels have received a great amount of criticism (The linked videos contains some spoilers). To be fair, the music (although repetitive), voice acting and even the way the story is presented are quite good, but everything is dragged down because of the animation style, which is one of the most hideous 3d CGI I have seen since Popee the Performer (but that was a parody, not a serious show like this). Apparently, they wanted to make the visuals worthy of the manga and they misjudge what was required to achieve that look, the staff didn't have the qualifications to take over this massive undertaking either, taking most of the time they had to create the show just for testing animation styles and then having to settle on what we currently have. Even so, these sequels rank fairly high (considering the badmouthing they received) and are currently the only way to continue the story other than reading the manga. The story still comes through, a testament to the greatness of the plot, themes, and characterization!

If you are a manga reader, then you'll probably be happier to just stick to the manga and forget of the anime altogether until a proper remake is done. 

These sequels were created 19 years after the first season, which gives me hope that the story will one day be completed (hopefully with a worthy remake and during my lifetime) and other shows that are also left incomplete may one day reach their ending. I can only dream!

The dub is good.

Watch. Continuation of the story.

And after 20 years, 1 remake, and 3 seasons later, we finally find out why this series is called "Berserk", it feels like we have barely reached the end of the first part and now the main story is about to begin!

The dub is good.

"On May 20, 2021, Hakusensha announced that Miura died at 54 due to an acute aortic dissection on May 6, leaving it undecided what would happen to the series." -Wikipedia

Skip, it's just a recap of the 2017 series.