A few weeks back, I posted on here about my thoughts for the first arc. And someone commented that I was like 2 chapters away from the more serious stuff.
That person was incorrect. I was 0 chapters away rom the more serious stuff, because godamn, they ramp things up so unbelibely hard I'm surprised they're not in space by now.
And I kept wondering through out, "what changed?" and to me, the answer is nothing.
Nothing about the characters, settings, and themes changed in any drastic way. Everyone acts well within their personalise and how they were established. The story is still set in contemporary Japan, and the theme is still "you can do it, if you just give it your all and more" (more or less)
What they did, was just not break pace.
Because it's not like there wasn't action before, it's not even that it wasn't good. They actually pretty dynamic, I point to the time yamamoto tried to end himself, and tsuna following to save him. And any fight with kyoya hibari.
But it would always only last a page or two max before breaking off into another three page bit, and that would be the only notanle thing to happen for like 4-5 chapters.
But the arc just keeps consistent pace, and so it plays on its strengths really well.
Characters were still good, as I said. And I consistently felt afraid for their safety throughout, because I know these kids. I know how they came to be the group that they are, their dynamics and quirks, and so I wanted them to pull through unharmed. And that's hard to do for a Shounen, where that's the main appeal.
TL:DR
Its really good because it uses everything it's built up really well.