Its FAB!!!
i went to a matinee and there were lots of noisy kiddies there at the time ( i was childless at the time). Its a noisy production so wouldn't upset the audience if your children wanted to make a bit of noise.
I think a confident 3 yr old who is capable of sitting still that long would love it. Can't recall anything too scary except for the acrobats swinging towards your head (made me duck!)
Not for a shy and retiring 3 yr old.