I have been there twice, and have also experienced the Pirate Dinner Adventure.
Medieval Times is much more fun, in my opinion. Even though I went there once already, it was still a fun experience the second time. I think your kid will enjoy it a lot! And the food portions are really generous.
Just be prepared for corny jokes, though.

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Katrina
Aspiring Disney Animator
Next Trips:
June 2007 - Grad Trip with C/O 2007 @ Disneyland!!
August 6-15, 2007 - Seattle, Vancouver, and Victoria!
October 31, 2007 - Halloween at Disneyland!
Yeah, I'm such a Disneyland snob.