The ending of the Shanks stuff was definitely better in the anime. Hard for a child actor to match the animation combined with high-level adult voice acting...Shanks losing an arm wasn't so dramatic. It's a definite negative that they didn't do the "the men before you are pirates" part, but instead had a bit more of a fight scene for Shanks' crew.
I do like the way it's structured, as in it transitions back and forth between flashbacks and the current story. It's hard to fit 14-15 hours of anime into 8 hours, but they've done a more than decent job.
Even though the general level is good, I do wonder if they'll hit any of the emotional highs of the anime properly, because so far I don't feel like they have. The fight choreography and cinematography are both great though - the choreography surprised me, because a lot of Hollywood has bad fight choreography.
Actors so far who are super great: Helmeppo, Luffy, Buggy(?), Coby
Actors so far who are great: Zoro, Nami
Actors ok: Kid Luffy, Garp, Morgan, Kid Luffy (for a kid), Shanks
Actors not as ok: Alvida