Unfortunatelly i already know a lot that happened and i remember trying to read a little of Punk Hazzard some months ago, i'm no longer doing it as i want to watch the rest of the story first but i read enough to have Law as one of my favourite characters too
I think One Piece deserves to have a thread around, i mean, it's the highest-selling manga in Japan (since the industry there is the biggest it also ends up being the highest selling manga worldwide, even if Naruto's generally more popular outside Japan), it even beat Dragon Ball's sales.
Naruto is near it's end, Bleach is in its final arc which may last 5 to 7 more years but are no longer in their prime, i heard the Fish Island arc was boring but OP still seems to have a lot to give even though it's the oldest.
I disagree with many that say the first arcs in One piece are bad (not in this thread but in the internet in general), some even say Fairy Tail's first arcs were better, but i also disagree with that notion, these first story arcs are quite good and emotional, not to mention that they set up well what's to come. It's only a shame that characters like Captain Kuro never showed up again, he didn't even have the oportunity to fight with his full strength.