As someone who's watched all the anime and read all the manga from the beginning, I've been watching the live action and so far really enjoying it.
No, the plot is not entirely accurate, the characters aren't 100% the same, but honestly I wouldn't want them to be. The One Piece manga and anime just wouldn't translate 100% to live action and be a good show. I think the adaptation and the changes they make work very well for a live action show (without spoiling anything).
The things they needed to get right, they did, IMO. For example, Luffy's pure optimism, the relationship within the straw hat crew, the emotional scenes (I cried a few times)...
A lot of people expect and want to see a 100% faithful adaptation, but that doesn't make sense to me. If I wanted to watch/read One Piece, I would just watch the anime or read the manga. As a OP fan, the live action serves a specific purpose for me which is just to relive some of the moments I watched as a kid with real people and to see different take on the story. I think the show achieved that.