I would do HDD.
reasons:
Great entertainmant for the whole family. Mention on your PS and when you get to the HDD any birthdays and anniversaries.
inside - great for any type of weather
Food to the liking of young kids - nothing gourmet. Rids, fried chicken, beans, corn - but a bit spicy, soda, milk, water, wine. And for pickey eaters- or special diets- you can get pizza, veggie platter, no salt foods, etc ...just tell then HDD 48 (or was it 24) hours ahead of time. Again, mention it when you make your PS.
Be prepared for funny slapstick - you will even see your sever dance when the strawberry short cake is served for desert.
Do make PS up to 2 years ahead of time - better seats, the earlier you do your PS.
earlier show may be best for under 7 crowd
boat ride from MK to HDD is a fun way to start
Buses (or boat) are easy to find for ride back to the resort
You can do a hay ride after the earlier HDD show
There are cute 'Indian/Western' motif gift carts out side the HDD
to look at or buy items
Best show at WDW - my DS never laughed so hard (at age 10)
My DH even said the coffee was not bad
own table to sit at with your family - theyt can sit 2 people or 12 people
LUAU
Fun show - very Polynesian - fire eaters, hula dancers
Wedding and Anniversary couples go up on stage to dance
Birthday kids pile up on stage and do the hula (sort of)
Food is OK. We were not thrilled at the selection
no choice of alternate meals
nothing to do while waiting to get into the Luau
picture taken had the sun in our eyes
long way back to the Dolphin - monorail then bus
a bit cool in the evening
if it rains to hard - then the show is cancelled - I am not sure about refunds
if it rains and the show goes on and you sit near the stage,
you will get wet
you sit at a long table with other families - can be good or bad
Just my 2 cents