Hi twirly!
I haven't been to either, so can't give you an opinion there, but I did want to let you know that if you are going to make a PS for Big River Grille, you have to call them directly. I had called Disney Dining, and the CM didn't even know what restaurant I was talking about!! After a few minutes, she came back with the number and said I had to call them myself... I did, was handed over to the general manager. Hopefully, everything will be set up when we arrive -- we're a party of 12!!
Good luck!