I started on One Piece with the old 4Kids dub which at the time I didn't make a big deal about it until I started watching it on both Funimation's English dub and the english subbed simulcasts that they have provided and along with the manga made One Piece my number one favorite series and realized exactly what I have missing out on (also taking note on how 4Kids badly ruined a great series like this one). Funimation's dub gave me a whole lot more to enjoy with voice actors that aced roles in shows like Dragon Ball Z, Yu Yu Hakusho, and Fullmetal Alchemist; their role in One Piece was definitely outstanding to say the least and I look forward for more episodes to come through Funimation.
As for One Piece itself, you definitely need to open your sense of grasping the story and try your best to not bog yourself down in the small details in the story, because there are too many small details to track in the ever expanding world of OP (even so today). Also, be prepared to experience a lot of emotions; One Piece can make you laughing hard one moment and then trying not to cry in the next. It has a compelling story and everything happens as if there was some kind of purpose as opposed to randomly making things happen in a desperate attempt to move the story.
The only down-side is that for short anime/manga fans...this one is really long (over 500 episodes and about 60 manga volumes). Unless if you're eager for this series, you won't be able to cover everything. There is some filler here and there, but not a lot and the filler is pretty nice. Once you get into it (probably after a couple of episodes, usually 2 or 3), you can see just how far the Straw Hats journeyed from where each of them has started. 9.5/10