The ship is actually a lot more fun than it seems. It's really great to whiz across the map and then climb onboard in midair and suddenly start dishing heavy damage. You can dismount/mount pretty quickly and you keep up the same mobility you had before. It's pretty interesting to manage the on/off mode, finding a compromise between power and speed.
Rapid Fire is mostly only for bossing and not very helpful except when your ship breaks. It's much weaker than Cannon. Elemental Boost is a decent skill, but I don't know anyone who didn't fall in love with the awesomeness of Torpedo once they got it to a good level. It is one of the best mob skills in the game. Definitely has to be maxed before EB.
Rapid Fire is mostly only for bossing and not very helpful except when your ship breaks. It's much weaker than Cannon. Elemental Boost is a decent skill, but I don't know anyone who didn't fall in love with the awesomeness of Torpedo once they got it to a good level. It is one of the best mob skills in the game. Definitely has to be maxed before EB.