I would go based on where you are going to visit.
With an 8 year old will you find yourself more in Epcot/HS or at MK? That would then decide if I pick a Deluxe next to one or the other.
From there you will just have a couple options each to compare which is straight forward from a room layout vs price comparison.
If I was staying Hotel side I would only ever do Boardwalk or Yacht Club but we are partial to the ease of access to Epcot for dinner every evening and festival booths.