I like the Grand Floridian because it is just a short monorail ride away from the Magic Kingdom.
The Boardwalk is just a short walk from Epcot, though.
Which parks do you visit more frequently? If MK and Epcot, then GF has monorail transportation to both. If it’s Epcot and DHS, then the Boardwalk has a boat to both.
I have never stayed at the Boardwalk, but I would venture to say that overall, the Grand Floridian offers more ammenities.
IMO, the Boardwalk is better for the DVC villas, which are along the Boardwalk. The Inn just isn’t as cute in theming.
The Boardwalk has a bigger waterslide, though.
It’s all about your vacation style.