It's very good but with glaring flaws.
It's game of thrones set in medieval northern Europe, political machinations among gory battle scenes.
Let's cast the characters:
Askeladd is the Hound or Jaime Lannister, we think he's a simplistic bad guy but the entire season follows him around and we realize he's a bad guy we like. He's the most well-written character of the series. Probably everyone's favorite character
Thorfinn, the main character, is basically Arya Stark. Can't touch this knife wielding plot armored shallow character, who's singular motivation is revenge for his father that he himself got killed by being a naïve child. Potential for plot development? Yeah but the writers decided not to and Thorfinn ends up being a thoroughly unlikable one dimensional character. Maybe next season will be better.
Cannute is reverse Daenerys. He goes from our least favorite character to our favorite character in one sudden abrupt transition. Cannute starts as a whiny little brat and then he undergoes puberty after discussing philosophy with a drunk priest. At that point onwards he becomes a likable contender for the throne.
Thorkell is the Mountain. He likes to fight, and that's basically his character.
So in summary, there are very good characters, and very bad characters. They all share about equal screentime so they balance each other out.
Plot: It's a slow burner, and as the title of episode 24 implies, this is just the prologue. Things start to pick up towards the end, with the political maneuvering, but they try to keep your interest with gory battles until then.
Battles are well-animated, gory, with actual direction unlike GOT S8. The feats of the main characters are a bit unrealistic, like cleaving people in half with a sword, throwing really heavy objects, things like that.
So who should watch it?
If you liked the first few seasons of GOT, either for the politics or the gore, you should watch it. If you like historical war dramas, you should watch it. If you can't stand annoying characters or unrealistic character development, stay away.