Can't say anything on quality as I never pay attention to it, but New World 4th Movement was greatThe anime has some Legitimately hype moments though.
When Luffy defeats Mr. 0 Crocodile it plays this amazingly cool classic music (From the New World) as he pelts the everloving shit out of him and its great.
I can't vouch for the anime's quality after Thriller Bark though, has it gotten better or worse?