The quality of first two seasons is good, and not great. The series has a strong start (episodes 1-4), and from episode 5 or 6 becomes plagued by mediocrity. My score for the first two seasons is 8/10.

The two seasons have a lot of suspense and action, and overall not much deep character work, emotion or story. (I am someone who seeks inspiration, wisdom, beauty and emotion in fictional works.) Its emotionally deepest story thread 'individual against society' is very good, and there is not enough of it in the series. The series made me want to keep watching to know what happens next and to find out the answer to all the mysteries, while the journey to those goals itself wasn't full filling enough.

While I liked a couple of the characters, and was invested in the one who had to 'fight society', I found most of the characters not very likeable. Many of them took seemingly 'stupid' actions or sometimes acted disrespectfully towards others. This sometimes made me not care about the fate of the characters. It also made slice of life scenes less interesting to watch.

I expect seasons 3 and 4 to be entertaining. I do not expect them to be fulfilling. So I do not feel motivated to watch them.

To give you an impression of my taste, these are some series I have rated highly in the past: 'Cyberpunk: Edgerunners', 'The Sandman', 'Violet Evergarden', 'Vivy: Fluorite Eye's Song ', 'Great Pretender', 'Messiah', 'The OA', 'Sense8', 'Beastars', 'Dark', and the movies 'Interstellar' and 'Arrival'.

Edit: I have watched seasons 3 and 4 now. My score for the whole show went down from 8/10 to 7/10.

Season 4 isn't as great as everyone seems to say it is. I kept waiting for season 4 to get good, but it never did. While the final episode is interesting, I didn't find it good enough to make the season worth finishing. This season there is even more action than before and even less mystery. There is also a lot of slice of life. It was a painful watch for someone who was looking for a deep or astonishing story. If you are someone without high expectations, who enjoys action scenes, and who is invested in the characters or loves them, you might enjoy this season.

On the other hand, season 3 isn't as bad as people say it is. I think it is better than season 2, because characters act less stupid, and the plot felt more concise. It's not great either, but it's solid entertainment.

My ranking: Season 1 > season 3 > season 2 > season 4.