I've done it both ways, Fort Wilderness (trailer rental, so didn't save money with BYO RV) and a hotel just off the property on International Drive, transportation to WDW included.
The Fort Wilderness experience was so much better, we felt free to spend more time in the theme parks (Magic Kingdom particularly), there were evening activities in the campground, and a greater sense of privacy, almost isolation, in our quarters.
But nothing quite beats staying in a hotel on the property (not International Drive). Service is very good to excellent, and you have access to everything, including off-hours activities (just different from campfires at Fort Wilderness). If I had the urge to revisit WDW (I don't, was escorting visitors there more than ten times the first 18 months it was open) I would likely book at the Polynesian, because the atmosphere fits me. Can you say luau?
But then, for the cost of a week or two at the Polynesian, I could probably get to Tahiti and experience the real thing, or at least a nice beachfront hotel on the Kona coast.
I do have a RV, I do travel a lot since retirement, but not every trip is a RV trip.
