Read the manga.
The One Piece anime is one of the worst anime adaptations of a manga I have ever watched.
1. The pacing.
Normally anime will adapt 2-3 chapters per episode, while One Piece will adapt 1 or even half a chapter into an episode. Thats like less than 8 pages an episode. If the pacing was good, One Piece would have like 500 episodes instead of 1000+
2. The animation.
The animation in early episodes was pretty bad and looked very rushed. It dosent get good until episode 892 when they switched to digital animation. The animation is incredible in the newest arcs it's probably the best animated shonen but that dont matter if the pacing is bad
3. The voice acting
The japanese version has some pretty good voice actors but the dub has mostly bad ones. Luffy's voice in the dub was fine at first, but the more you watch the more annoying he gets.
4. The story
The story is good. Thats why you should read the manga.
Overall 4/10
Bad adaptation to an amazing manga