For some reason, of all the restaurants on the dining plan, my kid picked THIS one as the one he most wants to go to. Reviews I've read have been mediocre-to-good.......I like the fact that on the dining plan you can "add a lobster for $12." to any entree and not have to pay the $12. I've heard some comments that this restaurant is overpriced (in case you're not on the dining plan, jm).......and that it's best to stick with a shrimp cocktail and a steak here.
Also I've heard that once you get to Downtown Disney it's a LONG WALK to Capn' Jacks, so if you have a reservation plan to arrive a little early.