I would say the Dolphin with a discount rate - which I hope you can secure (nurse, teacher, military, maybe others- it pays to call the S/D directly and ask reservations).
Reasons for the Dolphin:
1) closer to the Grotto pool and kiddie pool (depending on the ages of your children)
2) 360 sq foot room - very nice and large and now has mini real cold refrigerators to use
3) Picabu's is in the Dolphin and open 24 hours by 7 days a week for refillable mugs, snacks, food and some personal items if needed.
4) laundry is located in the Dolphin, as is the fitness center and game room
5) from the S/D you walk to EPCOT

take a boat to DHS (and EPCOT)

and walk over to the Boardwalk for activities and places to eat
6) there are always taxi's in front of the Dolphin to take you anywhere in a hurry (for a fee)
7) the staff has always been great for us - just call the front desk politely with any concerns, and you will be helped
8) you get 2 over sized heavenly beds and a cot will easiily fit between the bed and the window (or sliding glass doors, if you have a balcony)
9) join Starwood and earn points by staying at the S/D and also get a free upgrade if available (
www.starwood.com)
10) our last reason - we love

staying at the Dolphin