I love this anime it was very fun to watch. The real pirates were not near cute, they were brutes, vicious... but this is after all set in future and in anime, so everything is possible. Story arcs are good, very good i would say, however end is little weak, i would be nice if Marika in the end meet with her father. But even if its not, it is still good. Art, overall i like it very much, it is nicely done, ships are nicely designed, featuring old with new, grand cross on the other hand, zig-zaging which i hardly believe that would bepossible in real life, but nevertheless.
Sound, i love sound in this anime, it has that pirate flavor mixed with irish music, although i didnt like the opening song much.
Characters, Marika and her gang of pirates were nicely done, and all other side characters, all are good
Enjoyment, i really did enjoy

overall it is good but not good enough to deserve 10, nevertheless 9 is fair score for Mouretsu Pirates, and it is one of animes that definitley deserve second season, and i really hope there will be the season 2,