Surprise, I like him very much!
From my point of view, he is very similar to luffy, but also way closer to what pirates really are. A less romantic version you could say.
Also, he seems to be kinda a „what if“ version of Luffy. He is what would have been when Luffy had no legendary genetic (ok still unknown for kid), no legendary God deity DF, no Trainer which is one of the strongest in verse, not never ending plot armor…
And besides that, he has things which even show Luffys attributes in a stronger and better way.
for example we have the crew, the „family“. While luffy gathered them together on his journey and sticks to them, Kid has some of his crew (f.e. killer) since he is a child. They are like literally brothers, stick together since the childhood. And his whole crew shows similar behavior to the strawhats, they always care for each other (remember when they laughed with killer together, so he doesn’t need to feel embarrassed?). They might even be closer with each other than the strawhats.
also, they are at least as adventures as the strawhats, which was presented by oda when they said they never have stepped back from exploring an island. And they explicitly said exploring, not pirating.
And now, extremely important, his will.
While Luffys will is smashed in our face every chapter, it drains him further, but at what cost? None. He sometimes lose, but gets up immediately, gets some plot armor heal or timespan etc.. And with his loses, he never lose anything. All he lost was Ace, but that was not even connected to his strength, it was Aces own stupidness.
So Luffy never has to pay for stupid actions or for going to far against stronger opponents. Easy to keep his will then.
But Kid, he pushed himself to the level he is right now, just a few steps behind luffy, without a god DF, without a legendary mentor, without all these plotarmors, but with debts he had to pay.
He lost fights on his ways up and he had to pay for it. He lost his arm. His best friend gets mutilated with his laughter and so on. But still, Kid has kept his will, he is still going further, fighting for more. And he is ready to pay a debt for it. A debt Luffy doesn’t know it exists.