Hi,
When we went to Pirates DS was 9 and DD was 7.
I would say both enjoyed the pre-show (basically an attempt to extract as much money from you as possible) but I dont think either enjoyed the show.
This was a couple of years ago so I dont know if they've made any improvements.
We didn't have good seats and it was difficult to see what was going on.
Personnally we wont be going back.
I would buy tickets before you go. There are various discount coupons when you get there but I think you will get a better price buying before you go.