Nobest shonen? TTGL or FMA:B.
And no.One Piece ovverated
One Piece will make you fucking catch feels on the reg. Straight up fuck yo onion shit. I mean Ace. Fucking Ace. That was a rip your damn heart out your chest moment. Most writers don't have the balls to put their main character through the wringer for so long, have him struggle so hard, make him face insurmountable odds on insurmountable odds to win and win, only to snatch defeat for the jaws of victory at the very last moment. Oda is a brilliant writer and the fact that one piece has gone on for so long without (IMO) a drop in quality is a testament. You wouldn't expect it to be so damn excellent considering the art and the premise, but there is nothing that remotely touches One Piece. Every single character has a backstory that's good enough to be the protagonist of another series.