There's a lot of action, cannons going off, swashbuckling, ships being lost and found -- a typical Pirates film. So, yeah, a kid will enjoy it.
But in my not so humble opinion, the plot takes too many improbable leaps, characters lack or change motivation, random out of nowhere mcguffins... it seriously seems like the writers just got lazy and used all the unused ideas from the previous films (and which had been cut for good reason). Or maybe John Lasseter was advising the screenplay...
I will say this -- it is a visually stunning film, and I found it entertaining. But it wasn't one of the higher quality forays for Bruckheimer, as judged by my measure, which is impulse to buy the film when it comes out on DVD/Blu-ray. Just not there for me...