If I could give 10/10 to only one series, it would be this one.
The art improves by leaps and bounds after a while, and by ~ch 250 the story becomes so super cool, you won't have read anything like it.
Whenever I finish a manga, I feel a sense of contentment, but with this one, I feel melancholic because I'm positive I'll never read anything like that again, at least in manga form.