This one is easy , the market dictates the higher GF price and worth. I personally would rather stay at GF since it's a Disney trip , you stay in the bubble and you get onsite privedges like Fastpass and dining priority. Plus the location advantage which is obvious. You can find a 4 seasons in just about any major metro area
FS is located in the heart of Disney property and has a full character breakfast two days a week, so it's more "in the bubble" than other Disney hotels. This FS is pretty spectacular and was designed especially for WDW, with the best pool on property.