I've not watched the movie yet. But I've watched the anime series and also read the manga.
But some of my friends have watched it and they said it's nothing compared to the anime. Regardless, I plan on watching it in the future.
I would highly recommend you to watch the series. It has great laughs, awesome stories for every character and one of the best world building in fiction writing. If you cried at the end of this movie, then this series will take you on a ride of emotions.
If you plan on watching, I recommend you start with the One Pace project.
ALSO, VERY IMPORTANT: Next week the One Piece Live action series starts airing. If you plan on watching this anime in the future, stay away from anything related to one piece on the internet. Else you will be spoiled.