I'll step up since I've stayed at both resorts. I think it's best summed up by my then-6-yr-old son. When we left SOG, we drove by CSR on our way off property and he looked longingly at the entrance and said, "Can we go back to Coronado next time?" He was not impressed with SOG - none of us were, actually. It was OK, but it could have been anywhere, except for the big Mickey statue in the lobby. There was really nothing special about it. The food choices were poor, our room was shabby (but I understand they were refurbed not long after we were there), we thought the transportation was less efficient than CSR. Our room was a long walk from the lobby, then we usually walked another 15 minutes to the Poly to take the monorail to MK, or another 15 min walk to the TTC to monorail to Epcot. The SOG buses only leave once per hour for AK and DHS, otherwise you can take the TTC bus and get a Disney bus there to DHS or AK -- just seemed very long compared to hopping on one bus at CSR and being dropped off at the park gates. The best things about SOG are the larger rooms and balconies/patios (we were on the 1st floor and had a patio) -- for us, we don't spend that much time in our rooms so the size isn't that important, but the patio was nice, although in our location we only had a view of the restaurant.
Also, if you are driving or renting a car, realize that you have to pay either $5 or $10/ day in parking fees at SOG; if you are flying, realize that Magical Express does not service SOG, so you'll need a shuttle service, which adds expense.
When we stayed at SOG, we were with 2 other families; none of us plan to return. It was a nice resort, but like I said, it could have been anywhere - nothing special about it, IMO.
BUT, we LOVE CSR. It has a personality, which is sorely lacking at SOG. Is it worth $300? That's up to you!