We've been to both, and personally, I liked Medieval Times better. I think Pirates was fun, the appetizers were a great touch, and the show was very good. But, Pirates engages the crowd, and if people in your group are the "don't pick me" type, or don't like to play along, your enjoyment may be affected.
Medieval Times was more impressive to me. Although it is scripted, these people need real skill, and the only real audience participation is cheering for your knight.
As for food, it's decent at both places. You just need to keep in mind that they are cooking for the masses, and that shows, but it's still enjoyable.