I'll be brief with my review because this special episode does not have much to get, but here it goes. Basically it is an episode of recapitulation that summarizes the first three arcs of East Blue saga.
Story: 8. The summary of the story of the arcs of Alvida, the rescue of Zoro and the crew of Buggy is told by Luffy, as Zoro and Nami comment as they met. Personally I found it simple but entertaining.
Art: 10. It's the same kind of animation you see in the first 150 episodes, so it could not be better.
Sound: 9. Same original soundtrack.
Character:8. Same characters but
Luffy, Zoro and Nami's comments make it something fresh.
Enjoyment: 7. It was funny but i would like to watch a recap about the first 50 episodes. it would be great.
Overall: 8. I think it's enough. It's not bad but it is not something awsome.
It's worth for anyone who wants to get a little idea of what is One Piece before start watching the anime.